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Applied Microbiology and Biotechnology Mar 2024Environmental concerns about residues and the traditional disposal methods are driving the search for more environmentally conscious processes, such as pyrolysis and...
Environmental concerns about residues and the traditional disposal methods are driving the search for more environmentally conscious processes, such as pyrolysis and gasification. Their main final product is synthesis gas (syngas) composed of CO, CO, H, and methane. Syngas can be converted into various products using CO-tolerant microorganisms. Among them, Rhodospirillum rubrum is highlighted for its biotechnological potential. However, the extent to which high doses of CO affect its physiology is still opaque. For this reason, we have studied R. rubrum behavior under high levels of this gas (up to 2.5 bar), revealing a profound dependence on the presence or absence of light. In darkness, the key variable affected was the lag phase, where the highest levels of CO retarded growth to more than 20 days. Under light, R. rubrum ability to convert CO into CO and H depended on the presence of an additional carbon source, such as acetate. In those conditions where CO was completely exhausted, CO fixation was unblocked, leading to a diauxic growth. To enhance R. rubrum tolerance to CO in darkness, a UV-accelerated adaptive laboratory evolution (UVa-ALE) trial was conducted to isolate clones with shorter lag phases, resulting in the isolation of clones 1.4-2B and 1.7-2A. The adaptation of 1.4-2B was mainly based on mutated enzymes with a metabolic function, while 1.7-3A was mostly affected at regulatory genes, including the anti-repressor PpaA/AerR. Despite these mutations having slight effects on biomass and pigment levels, they successfully provoked a significant reduction in the lag phase (-50%). KEYPOINTS: • CO affects principally R. rubrum lag phase (darkness) and growth rate (light) • CO is converted to CO/H during acetate uptake and inhibits CO fixation (light) • UVa-ALE clones showed a 50% reduction in the lag phase (darkness).
Topics: Carbon Monoxide; Rhodospirillum rubrum; Carbon Dioxide; Acetates
PubMed: 38466440
DOI: 10.1007/s00253-024-13079-5 -
Canadian Journal of Microbiology May 2024This study characterizes seedling exudates of peas, tomatoes, and cucumbers at the level of chemical composition and functionality. A plant experiment confirmed that...
This study characterizes seedling exudates of peas, tomatoes, and cucumbers at the level of chemical composition and functionality. A plant experiment confirmed that bv. 3841 enhanced growth of pea shoots, while Sp7 supported growth of pea, tomato, and cucumber roots. Chemical analysis of exudates after 1 day of seedling incubation in water yielded differences between the exudates of the three plants. Most remarkably, cucumber seedling exudate did not contain detectable sugars. All exudates contained amino acids, nucleobases/nucleosides, and organic acids, among other compounds. Cucumber seedling exudate contained reduced glutathione. Migration on semi solid agar plates containing individual exudate compounds as putative chemoattractants revealed that bv. was more selective than , which migrated towards any of the compounds tested. Migration on semi solid agar plates containing 1:1 dilutions of seedling exudate was observed for each of the combinations of bacteria and exudates tested. Likewise, bv. and grew on each of the three seedling exudates, though at varying growth rates. We conclude that the seedling exudates of peas, tomatoes, and cucumbers contain everything that is needed for their symbiotic bacteria to migrate and grow on.
Topics: Solanum lycopersicum; Cucumis sativus; Seedlings; Rhizobium leguminosarum; Azospirillum brasilense; Pisum sativum; Plant Roots; Chemotaxis; Plant Exudates
PubMed: 38427979
DOI: 10.1139/cjm-2023-0217 -
Microbial Cell Factories Feb 2024We report the successful fabrication of a pharmaceutical cellular bank (PCB) containing magnetotactic bacteria (MTB), which belong to the Magnetospirillum...
We report the successful fabrication of a pharmaceutical cellular bank (PCB) containing magnetotactic bacteria (MTB), which belong to the Magnetospirillum gryphiswaldense MSR1 species. To produce such PCB, we amplified MTB in a minimal growth medium essentially devoid of other heavy metals than iron and of CMR (Carcinogenic, mutagenic and reprotoxic) products. The PCB enabled to acclimate MTB to such minimal growth conditions and then to produce highly pure magnetosomes composed of more than 99.9% of iron. The qualification of the bank as a PCB relies first on a preserved identity of the MTB compared with the original strain, second on genetic bacterial stability observed over 100 generations or under cryo-preservation for 16 months, third on a high level of purity highlighted by an absence of contaminating microorganisms in the PCB. Furthermore, the PCB was prepared under high-cell load conditions (9.10 cells/mL), allowing large-scale bacterial amplification and magnetosome production. In the future, the PCB could therefore be considered for commercial as well as research orientated applications in nanomedicine. We describe for the first-time conditions for setting-up an effective pharmaceutical cellular bank preserving over time the ability of certain specific cells, i.e. Magnetospirillum gryphiswaldense MSR1 MTB, to produce nano-minerals, i.e. magnetosomes, within a pharmaceutical setting.
Topics: Magnetosomes; Magnetospirillum; Iron; Pharmaceutical Preparations; Bacterial Proteins
PubMed: 38419080
DOI: 10.1186/s12934-024-02313-4 -
Biomolecules Jan 2024Previous work from our laboratory demonstrated that parental stress, induced by social isolation starting at puberty, leads to behavioral, endocrine, and biochemical...
Previous work from our laboratory demonstrated that parental stress, induced by social isolation starting at puberty, leads to behavioral, endocrine, and biochemical changes in the male, but not female, offspring (ISO-O) of Sprague-Dawley rats. Here, we report alterations in the gut microbiota composition of ISO-O vs. grouped-housed offspring (GH-O), although all animals received the same diet and were housed in the same conditions. Analysis of bacterial communities by next-generation sequencing (NGS) of 16S rRNA gene revealed alterations at family and order levels within the main phyla of Bacteroides, Proteobacteria, and Firmicutes, including an almost total deficit in (formerly ) and a significant increase in (formerly ). In addition, we found an increase in the relative abundance of Rhodospirillales and Clostridiales in the families of Lachnospiraceae and Ruminococcaceae, and Bacteroidales in the family of Prevotellaceae. Furthermore, we examined plasma levels of the proinflammatory cytokines interleukin-1-beta and tumor necrosis factor-alpha, which did not differ between the two groups, while corticosterone concentrations were significantly increased in ISO-O rats. Our findings suggest that adverse environmental conditions experienced by parents may have an impact on the likelihood of disease development in the subsequent generations.
Topics: Rats; Animals; Male; Rats, Sprague-Dawley; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Social Isolation; Lactobacillus
PubMed: 38397408
DOI: 10.3390/biom14020172 -
Journal of Clinical and Translational... Feb 2024Accumulating evidence highlights the association between the gut microbiota and liver cirrhosis. However, the role of the gut microbiota in liver cirrhosis remains...
BACKGROUND AND AIMS
Accumulating evidence highlights the association between the gut microbiota and liver cirrhosis. However, the role of the gut microbiota in liver cirrhosis remains unclear.
METHODS
We first assessed the differences in the composition of the bacterial community between CCl4-induced liver cirrhosis and control mice using 16S rRNA sequencing. We then performed a two-sample Mendelian randomization (MR) analysis to reveal the underlying causal relationship between the gut microbiota and liver cirrhosis. Causal relationships were analyzed using primary inverse variance weighting (IVW) and other supplemental MR methods. Furthermore, fecal samples from liver cirrhosis patients and healthy controls were collected to validate the results of the MR analysis.
RESULTS
Analysis of 16S rRNA sequencing indicated significant differences in gut microbiota composition between the cirrhosis and control groups. IVW analyses suggested that Alphaproteobacteria, Bacillales, NB1n, Rhodospirillales, , , and were positively correlated with the risk of liver cirrhosis, whereas , , , and displayed the opposite effects. However, the weighted median and MR-PRESSO estimates further showed that only and presented stable negative associations with liver cirrhosis. No significant heterogeneity or horizontal pleiotropy was observed in the sensitivity analysis. Furthermore, the result of 16S rRNA sequencing also showed that healthy controls had a higher relative abundance of and than liver cirrhosis patients.
CONCLUSIONS
Our study provides new causal evidence for the link between gut microbiota and liver cirrhosis, which may contribute to the discovery of novel strategies to prevent liver cirrhosis.
PubMed: 38343609
DOI: 10.14218/JCTH.2023.00259 -
International Journal of Biological... Mar 2024Bacterial cellulose (BC), a nanostructured material, is renowned for its excellent properties. However, its production by bacteria is costly due to low medium...
Bacterial cellulose (BC), a nanostructured material, is renowned for its excellent properties. However, its production by bacteria is costly due to low medium utilization and conversion rates. To enhance the yield of BC, this study aimed to increase BC yield through genetic modification, specifically by overexpressing bcsC and bcsD in Gluconacetobacter xylinus, and by developing a modified culture method to reduce medium viscosity by adding water during fermentation. As a result, BC yields of 5.4, 6.2, and 6.8 g/L were achieved from strains overexpressing genes bcsC, bcsD, and bcsCD, significantly surpassing the yield of 2.2 g/L from wild-type (WT) strains. In the modified culture, the BC yields of all four strains increased by >1 g/L with the addition of 20 mL of water during fermentation. Upon comparing the properties of BC, minimal differences were observed between the WT and pbcsC strains, as well as between the static and modified cultures. In contrast, BC produced by strains overexpressing bcsD had a denser microstructural network and exhibited demonstrated higher tensile strength and elongation-to-break. Compared to WT, BC from bcsD overexpressed strains also displayed enhanced crystallinity, higher degree of polymerization and improved thermal stability.
Topics: Gluconacetobacter xylinus; Cellulose; Fermentation; Nanostructures; Water
PubMed: 38242407
DOI: 10.1016/j.ijbiomac.2024.129552 -
Nucleic Acids Research Apr 2024Nitric oxide (NO) plays an essential role as signaling molecule in regulation of eukaryotic biomineralization, but its role in prokaryotic biomineralization is unknown....
Nitric oxide (NO) plays an essential role as signaling molecule in regulation of eukaryotic biomineralization, but its role in prokaryotic biomineralization is unknown. Magnetospirillum gryphiswaldense MSR-1, a model strain for studies of prokaryotic biomineralization, has the unique ability to form magnetosomes (magnetic organelles). We demonstrate here that magnetosome biomineralization in MSR-1 requires the presence of NsrRMg (an NO sensor) and a certain level of NO. MSR-1 synthesizes endogenous NO via nitrification-denitrification pathway to activate magnetosome formation. NsrRMg was identified as a global transcriptional regulator that acts as a direct activator of magnetosome gene cluster (MGC) and nitrification genes but as a repressor of denitrification genes. Specific levels of NO modulate DNA-binding ability of NsrRMg to various target promoters, leading to enhancing expression of MGC genes, derepressing denitrification genes, and repressing nitrification genes. These regulatory functions help maintain appropriate endogenous NO level. This study identifies for the first time the key transcriptional regulator of major MGC genes, clarifies the molecular mechanisms underlying NsrR-mediated NO signal transduction in magnetosome formation, and provides a basis for a proposed model of the role of NO in the evolutionary origin of prokaryotic biomineralization processes.
Topics: Bacterial Proteins; Magnetosomes; Magnetospirillum; Nitric Oxide; Nitrogen
PubMed: 38197240
DOI: 10.1093/nar/gkad1230 -
Frontiers in Immunology 2023The evolution of nutritional strategies to improve the gut health and microbiota profiles of early-weaned piglets is essential to reduce diarrhoea caused by weaning...
INTRODUCTION
The evolution of nutritional strategies to improve the gut health and microbiota profiles of early-weaned piglets is essential to reduce diarrhoea caused by weaning stress. Therefore, the aim of this study was to determine the effects of dietary supplementation of Qi-Weng-Huangbo powder, a traditional herbal medicine consisting of a mixture of , and extracts (PCE), on the growth performance, diarrhoea rate, immune function and intestinal health of weaned piglets.
METHODS
162 piglets were randomly assigned to the CON group (no PCE added), the PCEL group (300 mg/kg PCE) and the PCEH group (500 mg/kg PCE) at the end of the third week post farrowing. There were 9 replicates of each group with 6 pigs per replicate. The experiment lasted for 28 days and sampling was performed on the final day.
RESULTS
The results showed that the PCE diet increased the average daily gain (ADG) and final body weight (BW) compared to the CON group. Both supplemented doses of PCE reduced the faecal scores of piglets, and the diarrhoea rate in the PCEL group was significantly lower than that in the CON group. The application of PCE diets promoted the development of the spleen in piglets and up-regulated serum immunoglobulin concentrations to enhance immune function, which was also reflected in the down-regulated gene expression of the colonic TLR/MyD88/NF-κB pathway. Supplementation with PCE improved intestinal morphology, and all doses of PCE significantly increased villus height (VH) in the ileum, whereas colonic crypt depth (CD) was significantly lower in the PCEH group than in the CON group. The PCEH diet significantly increased the levels of valeric and isovaleric acid in the colon content. Dietary PCEH also improved the colonic microbial community profile, reflected by a significant increase in Shannon's index compared with CON group. The abundance of and was significantly increased in the PCEH group at the family level.
DISCUSSION
In conclusion, dietary PCE reduced diarrhoea rates, improved growth performance and enhanced immune function in weaned piglets. These improvements were potentially supported by altered ileum and colonic morphology, elevated colonic VFA levels, and modulation of colonic microbial profiles.
Topics: Animals; Swine; Powders; Qi; Weaning; Diet; Diarrhea; Immunity
PubMed: 38187371
DOI: 10.3389/fimmu.2023.1342852 -
Applied Microbiology and Biotechnology Dec 2024Gastric and colorectal cancer are among the most frequently diagnosed malignancies of the gastrointestinal tract. Searching for methods of therapy that complements...
Gastric and colorectal cancer are among the most frequently diagnosed malignancies of the gastrointestinal tract. Searching for methods of therapy that complements treatment or has a preventive effect is desirable. Bacterial metabolites safe for human health, which have postbiotic effect, are of interest recently. The study aimed to preliminary assessment of the safety, antimicrobial, and anti-cancer activity of cell-free metabolites of Gluconobacter oxydans strains isolated from Kombucha beverages as an example of the potential postbiotic activity of acetic acid bacteria (AAB). The study material consisted of five AAB strains of Kombucha origin and three human cell lines (gastric adenoma-AGS, colorectal adenoma-HT-29, and healthy cells derived from the endothelium of the human umbilical vein-HUVEC). Results of the study confirms the health safety and functional properties of selected AAB strains, including their potential postbiotic properties. The best potential anticancer activity of the AAB cell-free supernatants was demonstrated against AGS gastric adenoma cells. The conducted research proves the postbiotic potential of selected acetic acid bacteria, especially the KNS30 strain. KEY POINTS: •The beneficial and application properties of acetic acid bacteria are poorly studied. •Gluconobacter oxydans from Kombucha show a postbiotic activity. •The best anticancer activity of the G. oxydans showed against gastric adenoma.
Topics: Humans; Gluconobacter oxydans; Acetic Acid; Adenoma
PubMed: 38157006
DOI: 10.1007/s00253-023-12915-4 -
Current Biology : CB Jan 2024Cellulose is the world's most abundant biopolymer, and similar to its role as a cell wall component in plants, it is a prevalent constituent of the extracellular matrix...
Cellulose is the world's most abundant biopolymer, and similar to its role as a cell wall component in plants, it is a prevalent constituent of the extracellular matrix in bacterial biofilms. Although bacterial cellulose (BC) was first described in the 19 century, it was only recently revealed that it is produced by several distinct types of Bcs secretion systems that feature multiple accessory subunits in addition to a catalytic BcsAB synthase tandem. We recently showed that crystalline cellulose secretion in the Gluconacetobacter genus (α-Proteobacteria) is driven by a supramolecular BcsH-BcsD scaffold-the "cortical belt"-which stabilizes the synthase nanoarrays through an unexpected inside-out mechanism for secretion system assembly. Interestingly, while bcsH is specific for Gluconacetobacter, bcsD homologs are widespread in Proteobacteria. Here, we examine BcsD homologs and their gene neighborhoods from several plant-colonizing β- and γ-Proteobacteria proposed to secrete a variety of non-crystalline and/or chemically modified cellulosic polymers. We provide structural and mechanistic evidence that through different quaternary structure assemblies BcsD acts with proline-rich BcsH, BcsP, or BcsO partners across the proteobacterial clade to form synthase-interacting intracellular scaffolds that, in turn, determine the biofilm strength and architecture in species with strikingly different physiology and secreted biopolymers.
Topics: Cellulose; Proteobacteria; Gluconacetobacter; Bacteria; Biofilms
PubMed: 38141614
DOI: 10.1016/j.cub.2023.11.057