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Microbiology Spectrum Dec 2023Acetobacteraceae are one of the best known and most extensively studied groups of bacteria, which nowadays encompasses a variety of taxa that are very different from the...
Acetobacteraceae are one of the best known and most extensively studied groups of bacteria, which nowadays encompasses a variety of taxa that are very different from the vinegar-producing species defining the family. Our paper presents the most detailed phylogeny of all current taxa classified as , for which we propose a taxonomic revision. Several of such taxa inhabit some of the most extreme environments on the planet, from the deserts of Antarctica to the Sinai desert, as well as acidic niches in volcanic sites like the one we have been studying in Patagonia. Our work documents the progressive variation of the respiratory chain in early branching Acetobacteraceae into the different respiratory chains of acidophilic taxa such as and acetous taxa such as . Remarkably, several genomes retain remnants of ancestral photosynthetic traits and functional complexes. Thus, we propose that the common ancestor of was photosynthetic.
Topics: Acetobacteraceae; Phylogeny; RNA, Ribosomal, 16S; Acids; Antarctic Regions; DNA, Bacterial
PubMed: 37975678
DOI: 10.1128/spectrum.00575-23 -
Journal of Bacteriology Nov 2023, an industrial vinegar-producing strain, is suffered by fermentation stress such as fermentation heat and/or high concentrations of acetic acid. By an experimental...
, an industrial vinegar-producing strain, is suffered by fermentation stress such as fermentation heat and/or high concentrations of acetic acid. By an experimental evolution approach, we have obtained a stress-tolerant strain, exhibiting significantly increased growth and acetic acid fermentation ability at higher temperatures. In this study, we report that only the three gene mutations of ones accumulated during the adaptation process, , , and , were sufficient to reproduce the increased thermotolerance of . These mutations resulted in cell envelope modification, including increased phospholipid and lipopolysaccharide synthesis, increased respiratory activity, and cell size reduction. The phenotypic changes may cooperatively work to make the adapted cell thermotolerant by enhancing cell surface integrity, nutrient or oxygen availability, and energy generation.
Topics: Acetic Acid; Thermotolerance; Acetobacter; Fermentation; Amino Acids
PubMed: 37930061
DOI: 10.1128/jb.00101-23 -
Frontiers in Microbiology 2023Spontaneous fermentation of raw cow milk without backslopping is in practice worldwide as part of the traditional food culture, including "" preparation in earthen pots...
INTRODUCTION
Spontaneous fermentation of raw cow milk without backslopping is in practice worldwide as part of the traditional food culture, including "" preparation in earthen pots in Northeast India, "" of Niger and "" of Benin prepared in calabash vessels in West Africa. Very few reports are available about the differences in bacterial communities that evolved during the spontaneous mesophilic fermentation of cow milk in diverse geographical regions.
METHODS
In this study, we used high throughput amplicon sequencing of bacterial 16S rRNA gene to investigate 44 samples of naturally fermented homemade milk products and compared the bacterial community structure of these foods, which are widely consumed in Northeast India and Western Africa.
RESULTS AND DISCUSSION
The spontaneous milk fermentation shared the lactic acid bacteria, mainly belonging to and in these two geographically isolated regions. Indian samples showed a high bacterial diversity with the predominance of and , whereas was abundant in the West African samples. However, the cheese of Benin, prepared by curdling the milk with proteolytic leaf extract of followed by natural fermentation, contained spp.) as the dominant bacteria. Our analysis also detected several potential pathogens, like an emerging infectious foodborne pathogen in samples, an uncultured bacterium of in and samples, and spp. in the samples of Northeast India. These findings will allow us to develop strategies to address the safety issues related to spontaneous milk fermentation and implement technological interventions for controlled milk fermentation by designing starter culture consortiums for the sustainable production of uniform quality products with desirable functional and organoleptic properties.
PubMed: 37886068
DOI: 10.3389/fmicb.2023.1166518 -
PloS One 2023Lactobacilli and Acetobacter sp. are commercially important bacteria that often form communities in natural fermentations, including food preparations, spoilage, and in...
Lactobacilli and Acetobacter sp. are commercially important bacteria that often form communities in natural fermentations, including food preparations, spoilage, and in the digestive tract of the fruit fly Drosophila melanogaster. Communities of these bacteria are widespread and prolific, despite numerous strain-specific auxotrophies, suggesting they have evolved nutrient interdependencies that regulate their growth. The use of a chemically-defined medium (CDM) supporting the growth of both groups of bacteria would facilitate the identification of the molecular mechanisms for the metabolic interactions between them. While numerous CDMs have been developed that support specific strains of lactobacilli or Acetobacter, there has not been a medium formulated to support both genera. We developed such a medium, based on a previous CDM designed for growth of lactobacilli, by modifying the nutrient abundances to improve growth yield. We further simplified the medium by substituting casamino acids in place of individual amino acids and the standard Wolfe's vitamins and mineral stocks in place of individual vitamins and minerals, resulting in a reduction from 40 to 8 stock solutions. These stock solutions can be used to prepare several CDM formulations that support robust growth of numerous lactobacilli and Acetobacters. Here, we provide the composition and several examples of its use, which is important for tractability in dissecting the genetic and metabolic basis of natural bacterial species interactions.
Topics: Animals; Acetobacter; Lactobacillus; Drosophila melanogaster; Bacteria; Vitamins
PubMed: 37824485
DOI: 10.1371/journal.pone.0292585 -
Applied and Environmental Microbiology Oct 2023Gut microbiota are fundamentally important for healthy function in animal hosts. is a powerful system for understanding host-microbiota interactions, with modulation of...
Gut microbiota are fundamentally important for healthy function in animal hosts. is a powerful system for understanding host-microbiota interactions, with modulation of the microbiota inducing phenotypic changes that are conserved across animal taxa. Qualitative differences in diet, such as preservatives and dietary yeast batch variation, may affect fly health indirectly via microbiota, and may potentially have hitherto uncharacterized effects directly on the fly. These factors are rarely considered, controlled, and are not standardized among laboratories. Here, we show that the microbiota's impact on fly triacylglyceride (TAG) levels-a commonly-measured metabolic index-depends on both preservatives and yeast, and combinatorial interactions among the three variables. In studies of conventional, axenic, and gnotobiotic flies, we found that microbial impacts were apparent only on specific yeast-by-preservative conditions, with TAG levels determined by a tripartite interaction of the three experimental factors. When comparing axenic and conventional flies, we found that preservatives caused more variance in host TAG than microbiota status, and certain yeast-preservative combinations even reversed effects of microbiota on TAG. Preservatives had major effects in axenic flies, suggesting either direct effects on the fly or indirect effects via media. However, buffers the fly against this effect, despite the preservatives inhibiting growth, indicating that this bacterium benefits the host in the face of mutual environmental toxicity. Our results suggest that antimicrobial preservatives have major impacts on host TAG, and that microbiota modulates host TAG dependent on the combination of the dietary factors of preservative formula and yeast batch. IMPORTANCE is a premier model for microbiome science, which has greatly enhanced our understanding of the basic biology of host-microbe interactions. However, often overlooked factors such as dietary composition, including yeast batch variability and preservative formula, may confound data interpretation of experiments within the same lab and lead to different findings when comparing between labs. Our study supports this notion; we find that the microbiota does not alter host TAG levels independently. Rather, TAG is modulated by combinatorial effects of microbiota, yeast batch, and preservative formula. Specific preservatives increase TAG even in germ-free flies, showing that a commonplace procedure in fly husbandry alters metabolic physiology. This work serves as a cautionary tale that fly rearing methodology can mask or drive microbiota-dependent metabolic changes and also cause microbiota-independent changes.
Topics: Animals; Drosophila; Gastrointestinal Microbiome; Drosophila melanogaster; Acetobacter; Diet
PubMed: 37800920
DOI: 10.1128/aem.00165-23 -
ACS Applied Bio Materials Sep 2023There is a growing interest in developing natural hydrogel-based scaffolds to culture cells in a three-dimensional (3D) millieu that better mimics the cells'...
There is a growing interest in developing natural hydrogel-based scaffolds to culture cells in a three-dimensional (3D) millieu that better mimics the cells' microenvironment. A promising approach is to use hydrogels from animal tissues, such as decellularized extracellular matrices; however, they usually exhibit suboptimal mechanical properties compared to native tissue and their composition with hundreds of different protein complicates to elucidate which stimulus triggers cell's responses. As simpler scaffolds, type I collagen hydrogels are used to study cell behavior in mechanobiology even though they are also softer than native tissues. In this work, type I collagen is mixed with bacterial nanocellulose fibers (BCf) to develop reinforced scaffolds with mechanical properties suitable for 3D cell culture. BCf were produced from blended pellicles biosynthesized from . Then, BCf were mixed with concentrated collagen from rat-tail tendons to form composite hydrogels. Confocal laser scanning microscopy and scanning electron microscopy images confirmed the homogeneous macro- and microdistribution of both natural polymers. Porosity analysis confirmed that BCf do not disrupt the scaffold structure. Tensile strength and rheology measurements demonstrated the reinforcement action of BCf (43% increased stiffness) compared to the collagen hydrogel while maintaining the same viscoelastic response. Additionally, this reinforcement of collagen hydrogels with BCf offers the possibility to mix cells before gelation and then proceed to the culture of the 3D cell scaffolds. We obtained scaffolds with human bone marrow-derived mesenchymal stromal cells or human fibroblasts within the composite hydrogels, allowing a homogeneous 3D viable culture for at least 7 days. A smaller surface shrinkage in the reinforced hydrogels compared to type I collagen hydrogels confirmed the strengthening of the composite hydrogels. These collagen hydrogels reinforced with BCf might emerge as a promising platform for 3D organ modeling, tissue-engineering applications, and suitable to conduct fundamental mechanobiology studies.
Topics: Humans; Animals; Rats; Collagen Type I; Cell Culture Techniques, Three Dimensional; Fibroblasts; Gluconacetobacter xylinus; Hydrogels
PubMed: 37669535
DOI: 10.1021/acsabm.3c00126 -
BMC Ecology and Evolution Aug 2023Rodents form the largest order among mammals in terms of species diversity, and home range is the area where an individual normally moves during its normal daily...
BACKGROUND
Rodents form the largest order among mammals in terms of species diversity, and home range is the area where an individual normally moves during its normal daily activities. Information about rodent home ranges is paramount in the development of effective conservation and management strategies. This is because rodent home range varies within species and different habitats. In Uganda, tropical high altitude forests such as the Mabira Central Forest Reserve are experiencing continuous disturbance. However, information on rodent home range is lacking. Therefore, a two year Capture-Mark-Release (CMR) of rodents was conducted in the intact forest habitat: Wakisi, regenerating forest habitat: Namananga, and the depleted forest habitat: Namawanyi of Mabira Central Forest Reserve in order to determine the dominant rodent species, their home ranges, and factors affecting these home ranges. The home ranges were determined by calculating a minimum convex polygon with an added boundary strip of 5 m.
RESULTS
Overall, the most dominant rodent species were: Lophuromys stanleyi, Hylomyscus stella, Praomys jacksoni Mastomys natalensis, Lophuromys ansorgei, and Lemniscomys striatus. H. stella dominated the intact forest habitat, while L. stanleyi was the most dominant both in the regenerating and the depleted forest habitats. L. stanleyi had a larger home range in the depleted forest, and the regenerating forest habitats, respectively. In the regenerating forest habitat, M. natalensis had a larger home range size, followed by L. stanleyi, and L. striatus. While in the intact forest habitat, H. stella had the largest home range followed by P. jacksoni. H. stella, L. striatus, L. stanleyi, M. natalensis, and P. jacksoni were most dominant during the wet season while L. ansorgei was relatively more dominant during the dry season. L. ansorgei, and P. jacksoni had a larger home range in the dry season, and a lower home range in the wet season. H. stella, L. stanleyi, M. natalansis and L.striatus had larger home ranges in the wet season, and lower home ranges in the dry season. The home ranges of the dominant rodent species varied across the three habitats in Mabira central forest reserve ([Formula: see text], [Formula: see text]).
CONCLUSION
The significant variation in home ranges of the dominant rodent species in Mabira Central Forest Reserve depending on the type of habitat presupposes that the rodent management strategies in disturbed forest reserves should focus on the type of habitat.
Topics: Animals; Homing Behavior; Uganda; Forests; Acetobacteraceae; Murinae
PubMed: 37605119
DOI: 10.1186/s12862-023-02148-4 -
Microbial Biotechnology Sep 2023The excessive consumption of alcohol results in a dysbiosis of the gut microbiota, which subsequently impairs the gut microbiota-brain/liver axes and induces cognitive...
The excessive consumption of alcohol results in a dysbiosis of the gut microbiota, which subsequently impairs the gut microbiota-brain/liver axes and induces cognitive dysfunction and hepatic injury. This study aimed to investigate the potential effect of Acetobacter pasteurianus BP2201 in reducing the negative effects of alcohol consumption on cognitive function and liver health by modulating the gut microbiota-brain/liver axes. Treatment with A. pasteurianus BP2201 improved alcohol-induced hippocampal damage, suppressed neuroinflammation, promoted neuroprotein expression in the hippocampus and enhanced cognitive function. At the same time, A. pasteurianus BP2201 can also reduce serum lipid levels, relieve oxidative stress, inhibit TLR4/MyD88/NF-κB pathway, reduce the secretion of TNF-α and IL-1β, so as to improve alcoholic liver injury. Concomitantly, the treatment with A. pasteurianus BP2201 leads to a shift in the intestinal microbiota structure towards that of healthy individuals, inhibiting the proliferation of harmful bacteria and promoting the recovery of beneficial bacteria. In addition, it also improves brain cognitive dysfunction and liver health by affecting the gut microbiota-brain/liver axes by promoting the synthesis of relevant amino acids and the metabolism of nucleotide base components. These findings demonstrate the potential of regulating the gut microbiome and gut microbiota-brain/liver axes to mitigate alcohol-induced disease.
Topics: Mice; Animals; Gastrointestinal Microbiome; Liver; Ethanol; Acetobacter; Mice, Inbred C57BL; Dysbiosis
PubMed: 37354051
DOI: 10.1111/1751-7915.14303 -
International Journal of Biological... Jul 2023The microbial production of cellulose using different bacterial species has been extensively examined for various industrial applications. However, the...
Production efficiency and properties of bacterial cellulose membranes in a novel grape pomace hydrolysate by Komagataeibacter melomenusus AV436 and Komagataeibacter xylinus LMG 1518.
The microbial production of cellulose using different bacterial species has been extensively examined for various industrial applications. However, the cost-effectiveness of all these biotechnological processes is strongly related to the culture medium for bacterial cellulose (BC) production. Herein, we examined a simple and modified procedure for preparing grape pomace (GP) hydrolysate, without enzymatic treatment, as a sole growth medium for BC production by acetic acid bacteria (AAB). The central composite design (CCD) was used to optimise the GP hydrolysate preparation toward the highest reducing sugar contents (10.4 g/L) and minimal phenolic contents (4.8 g/L). The experimental screening of 4 differently prepared hydrolysates and 20 AAB strains identified the recently described species Komagataeibacter melomenusus AV436 as the most efficient BC producer (up to 1.24 g/L dry BC membrane), followed by Komagataeibacter xylinus LMG 1518 (up to 0.98 g/L dry BC membrane). The membranes were synthesized in only 4 days of bacteria culturing, 1 st day with shaking, followed by 3 days of static incubation. The produced BC membranes in GP-hydrolysates showed, in comparison to the membranes made in a complex RAE medium 34 % reduction of crystallinity index with the presence of diverse cellulose allomorphs, presence of GP-related components within the BC network responsible for the increase of hydrophobicity, the reduction of thermal stability and 48.75 %, 13.6 % and 43 % lower tensile strength, tensile modulus, and elongation, respectively. Here presented study is the first report on utilising a GP-hydrolysate without enzymatic treatment as a sole culture medium for efficient BC production by AAB, with recently described species Komagataeibacter melomenusus AV436 as the most efficient producer in this type of food-waste material. The scale-up protocol of the scheme presented here will be needed for the cost-optimisation of BC production at the industrial levels.
Topics: Vitis; Cellulose; Gluconacetobacter xylinus; Acetobacteraceae; Biotechnology; Acetic Acid
PubMed: 37330080
DOI: 10.1016/j.ijbiomac.2023.125368 -
New Biotechnology Sep 2023The development of bacterial cellulose (BC) industrialization has been seriously affected by its production. Mannose/mannan is an essential component in many biomass...
The development of bacterial cellulose (BC) industrialization has been seriously affected by its production. Mannose/mannan is an essential component in many biomass resources, but Komagataeibacter xylinus uses mannose in an ineffective way, resulting in waste. The aim of this study was to construct recombinant bacteria to use mannose-rich biomass efficiently as an alternative and inexpensive carbon source in place of the more commonly used glucose. This strategy aimed at modification of the mannose catabolic pathway via genetic engineering of K. xylinus ATCC 23770 strain through expression of mannose kinase and phosphomannose isomerase genes from the Escherichia coli K-12 strain. Recombinant and wild-type strains were cultured under conditions of glucose and mannose respectively as sole carbon sources. The fermentation process and physicochemical properties of BC were investigated in detail in the strains cultured in mannose media. The comparison showed that with mannose as the sole carbon source, the BC yield from the recombinant strain increased by 84%, and its tensile strength and elongation were increased 1.7 fold, while Young's modulus was increased 1.3 fold. The results demonstrated a successful improvement in BC yield and properties on mannose-based medium compared with the wild-type strain. Thus, the strategy of modifying the mannose catabolic pathway of K. xylinus is feasible and has significant potential in reducing the production costs for industrial production of BC from mannose-rich biomass.
Topics: Mannose; Cellulose; Escherichia coli K12; Gluconacetobacter xylinus; Glucose; Carbon
PubMed: 37182820
DOI: 10.1016/j.nbt.2023.05.002