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Toxins Jun 2022Patulin is a mycotoxin that primarily contaminate apples and apple products. Whole cell or cell-free extracts of ATCC 621 were able to transform patulin to E-ascladiol....
Patulin is a mycotoxin that primarily contaminate apples and apple products. Whole cell or cell-free extracts of ATCC 621 were able to transform patulin to E-ascladiol. Proteins from cell-free extracts were separated by anion exchange chromatography and fractions with patulin transformation activity were subjected to peptide mass fingerprinting, enabling the identification of two NADPH dependent short chain dehydrogenases, GOX0525 and GOX1899, with the requisite activity. The genes encoding these enzymes were expressed in and purified. Kinetic parameters for patulin reduction, as well as pH profiles and thermostability were established to provide further insight on the potential application of these enzymes for patulin detoxification.
Topics: Escherichia coli; Furans; Gluconobacter oxydans; Malus; Oxidoreductases; Patulin
PubMed: 35878161
DOI: 10.3390/toxins14070423 -
BioMed Research International 2013The knowledge of the survival of inoculated fungal and bacterial strains in field and the effects of their release on the indigenous microbial communities has been of... (Review)
Review
The knowledge of the survival of inoculated fungal and bacterial strains in field and the effects of their release on the indigenous microbial communities has been of great interest since the practical use of selected natural or genetically modified microorganisms has been developed. Soil inoculation or seed bacterization may lead to changes in the structure of the indigenous microbial communities, which is important with regard to the safety of introduction of microbes into the environment. Many reports indicate that application of microbial inoculants can influence, at least temporarily, the resident microbial communities. However, the major concern remains regarding how the impact on taxonomic groups can be related to effects on functional capabilities of the soil microbial communities. These changes could be the result of direct effects resulting from trophic competitions and antagonistic/synergic interactions with the resident microbial populations, or indirect effects mediated by enhanced root growth and exudation. Combination of inoculants will not necessarily produce an additive or synergic effect, but rather a competitive process. The extent of the inoculation impact on the subsequent crops in relation to the buffering capacity of the plant-soil-biota is still not well documented and should be the focus of future research.
Topics: Agricultural Inoculants; Azospirillum; Plant Roots; Rhizosphere; Soil Microbiology
PubMed: 23957006
DOI: 10.1155/2013/863240 -
BMC Microbiology May 2019Bacterial chemotaxis, the ability of motile bacteria to navigate gradients of chemicals, plays key roles in the establishment of various plant-microbe associations,...
BACKGROUND
Bacterial chemotaxis, the ability of motile bacteria to navigate gradients of chemicals, plays key roles in the establishment of various plant-microbe associations, including those that benefit plant growth and crop productivity. The motile soil bacterium Azospirillum brasilense colonizes the rhizosphere and promotes the growth of diverse plants across a range of environments. Aerotaxis, or the ability to navigate oxygen gradients, is a widespread behavior in bacteria. It is one of the strongest behavioral responses in A. brasilense and it is essential for successful colonization of the root surface. Oxygen is one of the limiting nutrients in the rhizosphere where density and activity of organisms are greatest. The aerotaxis response of A. brasilense is also characterized by high precision with motile cells able to detect narrow regions in a gradient where the oxygen concentration is low enough to support their microaerobic lifestyle and metabolism.
RESULTS
Here, we present a mathematical model for aerotaxis band formation that captures most critical features of aerotaxis in A. brasilense. Remarkably, this model recapitulates experimental observations of the formation of a stable aerotactic band within 2 minutes of exposure to the air gradient that were not captured in previous modeling efforts. Using experimentally determined parameters, the mathematical model reproduced an aerotactic band at a distance from the meniscus and with a width that matched the experimental observation.
CONCLUSIONS
Including experimentally determined parameter values allowed us to validate a mathematical model for aerotactic band formation in spatial gradients that recapitulates the spatiotemporal stability of the band and its position in the gradient as well as its overall width. This validated model also allowed us to capture the range of oxygen concentrations the bacteria prefer during aerotaxis, and to estimate the effect of parameter values (e.g. oxygen consumption rate), both of which are difficult to obtain in experiments.
Topics: Azospirillum brasilense; Chemotaxis; Models, Theoretical; Oxygen; Rhizosphere
PubMed: 31101077
DOI: 10.1186/s12866-019-1468-9 -
Scientific Reports Aug 2020Collective motion is found at all scales in biological and artificial systems, and extensive research is devoted to describing the interplay between interactions and...
Collective motion is found at all scales in biological and artificial systems, and extensive research is devoted to describing the interplay between interactions and external cues in collective dynamics. Magnetotactic bacteria constitute a remarkable example of living organisms for which motion can be easily controlled remotely. Here, we report a new type of collective motion where a uniform distribution of magnetotactic bacteria is rendered unstable by a magnetic field. A new state of "bacterial magneto-convection" results, wherein bacterial plumes emerge spontaneously perpendicular to an interface and develop into self-sustained flow convection cells. While there are similarities to gravity driven bioconvection and the Rayleigh-Bénard instability, these rely on a density mismatch between layers of the fluids. Remarkably, here no external forces are applied on the fluid and the magnetic field only exerts an external torque aligning magnetotactic bacteria with the field. Using a theoretical model based on hydrodynamic singularities, we capture quantitatively the instability and the observed long-time growth. Bacterial magneto-convection represents a new class of collective behaviour resulting only from the balance between hydrodynamic interactions and external alignment.
Topics: Bacterial Physiological Phenomena; Convection; Hydrodynamics; Magnetic Fields; Magnetospirillum; Models, Theoretical
PubMed: 32782266
DOI: 10.1038/s41598-020-70270-0 -
Proceedings of the National Academy of... Feb 2015There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform...
There are longstanding and ongoing controversies about the abiotic or biological origin of nanocrystals of magnetite. On Earth, magnetotactic bacteria perform biomineralization of intracellular magnetite nanoparticles under a controlled pathway. These bacteria are ubiquitous in modern natural environments. However, their identification in ancient geological material remains challenging. Together with physical and mineralogical properties, the chemical composition of magnetite was proposed as a promising tracer for bacterial magnetofossil identification, but this had never been explored quantitatively and systematically for many trace elements. Here, we determine the incorporation of 34 trace elements in magnetite in both cases of abiotic aqueous precipitation and of production by the magnetotactic bacterium Magnetospirillum magneticum strain AMB-1. We show that, in biomagnetite, most elements are at least 100 times less concentrated than in abiotic magnetite and we provide a quantitative pattern of this depletion. Furthermore, we propose a previously unidentified method based on strontium and calcium incorporation to identify magnetite produced by magnetotactic bacteria in the geological record.
Topics: Analysis of Variance; Biomarkers; Cell Culture Techniques; Fermentation; Ferrosoferric Oxide; Magnetite Nanoparticles; Magnetospirillum; Microscopy, Electron, Transmission; Trace Elements
PubMed: 25624469
DOI: 10.1073/pnas.1414112112 -
Scientific Reports Jun 2018Selecting appropriate tools providing reliable quantitative measures of individual populations in biofilms is critical as we now recognize their true polymicrobial and...
Selecting appropriate tools providing reliable quantitative measures of individual populations in biofilms is critical as we now recognize their true polymicrobial and heterogeneous nature. Here, plate count, quantitative real-time polymerase chain reaction (q-PCR) and peptide nucleic acid probe-fluorescence in situ hybridization (PNA-FISH) were employed to quantitate cystic fibrosis multispecies biofilms. Growth of Pseudomonas aeruginosa, Inquilinus limosus and Dolosigranulum pigrum was assessed in dual- and triple-species consortia under oxygen and antibiotic stress. Quantification methods, that were previously optimized and validated in planktonic consortia, were not always in agreement when applied in multispecies biofilms. Discrepancies in culture and molecular outcomes were observed, particularly for triple-species consortia and antibiotic-stressed biofilms. Some differences were observed, such as the higher bacterial counts obtained by q-PCR and/or PNA-FISH (≤4 log cells/cm) compared to culture. But the discrepancies between PNA-FISH and q-PCR data (eg D. pigrum limited assessment by q-PCR) demonstrate the effect of biofilm heterogeneity in method's reliability. As the heterogeneity in biofilms is a reflection of a myriad of variables, tailoring an accurate picture of communities´ changes is crucial. This work demonstrates that at least two, but preferentially three, quantification techniques are required to obtain reliable measures and take comprehensive analysis of polymicrobial biofilm-associated infections.
Topics: Anti-Bacterial Agents; Biofilms; Carnobacteriaceae; Cystic Fibrosis; Humans; In Situ Hybridization, Fluorescence; Rhodospirillaceae
PubMed: 29934504
DOI: 10.1038/s41598-018-27497-9 -
Journal of Molecular Microbiology and... 2009Acetic acid bacteria are a distinct group of microorganisms within the family Acetobacteriaceae. They are characterized by their ability to incompletely oxidize a wide... (Review)
Review
Acetic acid bacteria are a distinct group of microorganisms within the family Acetobacteriaceae. They are characterized by their ability to incompletely oxidize a wide range of carbohydrates and alcohols. The great advantage of these reactions is that many substrates are regio- and stereoselectively oxidized. This feature is already exploited in several combined biotechnological-chemical procedures for the synthesis of sugar derivatives. Therefore, it is important to understand the basic concepts of this type of physiology to construct strains for improved or new oxidative fermentations. Based on the genome sequence of Gluconobacteroxydans, we will shed light on the central carbon metabolism, the composition of the respiratory chain and the analysis of uncharacterized oxidoreductases. In this context, the role of membrane-bound and -soluble dehydrogenases are of major importance in the process of incomplete oxidation. Other topics deal with the question of how these organisms generate energy and assimilate carbon. Furthermore, we will discuss how acetic acid bacteria thrive in their nutrient-rich environment and how they outcompete other microorganisms.
Topics: Acetic Acid; Acetobacteraceae; Gene Expression Regulation, Bacterial; Genome, Bacterial; Gluconobacter oxydans; Oxidation-Reduction
PubMed: 18957863
DOI: 10.1159/000142895 -
Applied and Environmental Microbiology Jun 2021Nitrogen requirements for modern agriculture far exceed the levels of bioavailable nitrogen in most arable soils. As a result, the addition of nitrogen fertilizer is...
Nitrogen requirements for modern agriculture far exceed the levels of bioavailable nitrogen in most arable soils. As a result, the addition of nitrogen fertilizer is necessary to sustain productivity and yields, especially for cereal crops, the planet's major calorie suppliers. Given the unsustainability of industrial fertilizer production and application, engineering biological nitrogen fixation directly at the roots of plants has been a grand challenge for biotechnology. Here, we designed and tested a potentially broadly applicable metabolic engineering strategy for the overproduction of ammonia in the diazotrophic symbiont Azospirillum brasilense. Our approach is based on an engineered unidirectional adenylyltransferase (uAT) that posttranslationally modifies and deactivates glutamine synthetase (GS), a key regulator of nitrogen metabolism in the cell. We show that this circuit can be controlled inducibly, and we leveraged the inherent self-contained nature of our posttranslational approach to demonstrate that multicopy redundancy can improve strain evolutionary stability. uAT-engineered is capable of producing ammonia at rates of up to 500 μM h unit of OD (optical density at 600 nm). We demonstrated that when grown in coculture with the model monocot Setaria viridis, these strains increase the biomass and chlorophyll content of plants up to 54% and 71%, respectively, relative to the wild type (WT). Furthermore, we rigorously demonstrated direct transfer of atmospheric nitrogen to extracellular ammonia and then plant biomass using isotopic labeling: after 14 days of cocultivation with engineered uAT strains, 9% of chlorophyll nitrogen in seedlings was derived from diazotrophically fixed dinitrogen, whereas no nitrogen was incorporated in plants cocultivated with WT controls. This rational design for tunable ammonia overproduction is modular and flexible, and we envision that it could be deployable in a consortium of nitrogen-fixing symbiotic diazotrophs for plant fertilization. Nitrogen is the most limiting nutrient in modern agriculture. Free-living diazotrophs, such as , are common colonizers of cereal grasses and have the ability to fix nitrogen but natively do not release excess ammonia. Here, we used a rational engineering approach to generate ammonia-excreting strains of . Our design features posttranslational control of highly conserved central metabolism, enabling tunability and flexibility of circuit placement. We found that our strains promote the growth and health of the model grass and rigorously demonstrated that in comparison to WT controls, our engineered strains can transfer nitrogen from N gas to plant biomass. Unlike previously reported ammonia-producing mutants, our rationally designed approach easily lends itself to further engineering opportunities and has the potential to be broadly deployable.
Topics: Ammonia; Azospirillum brasilense; Glutamate-Ammonia Ligase; Pheophytins; Protein Processing, Post-Translational; Setaria Plant; Symbiosis
PubMed: 33962983
DOI: 10.1128/AEM.00582-21 -
International Journal of Environmental... Jan 2022Biorefineries are attracting attention as an alternative to the petroleum industry to reduce carbon emissions and achieve sustainable development. In particular, because...
Biorefineries are attracting attention as an alternative to the petroleum industry to reduce carbon emissions and achieve sustainable development. In particular, because forests play an important role in potentially reducing greenhouse gas emissions to net zero, alternatives to cellulose produced by plants are required. Bacterial cellulose (BC) can prevent deforestation and has a high potential for use as a biomaterial in various industries such as food, cosmetics, and pharmaceuticals. This study aimed to improve BC production from lignocellulose, a sustainable feedstock, and to optimize the culture conditions for using hydrolysates as a medium. The productivity of BC was improved using statistical optimization of the major culture parameters which were as follows: temperature, 29 °C; initial pH, 5.1; and sodium alginate concentration, 0.09% (/). The predicted and actual values of BC production in the optimal conditions were 14.07 g/L and 14.88 g/L, respectively, confirming that our prediction model was statistically significant. Additionally, BC production using hydrolysates was 1.12-fold higher than in the control group (commercial glucose). Our result indicate that lignocellulose can be used in the BC production processes in the near future.
Topics: Carbon; Cellulose; Culture Media; Gluconacetobacter xylinus; Glucose
PubMed: 35055692
DOI: 10.3390/ijerph19020866 -
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