scholarly journals Interaction between microbes, iron and chlorine for the development of biotechnological approaches to stabilize corroded iron

2017 ◽  
Author(s):  
◽  
Lucrezia Comensoli
Keyword(s):  
Iron Uptake ◽  
Direct Method ◽  
Resistance Mechanism ◽  
Corrosion Layer ◽  
Iron Bioavailability ◽  
Archaeological Iron ◽  
Minerals Production ◽  
Desulfitobacterium Hafniense ◽  
Efficient Uptake ◽  
Bacteria And Fungi

Iron objects suffer inexorable oxidation and without any human intervention they would be completely damaged. This phenomenon occurs for iron surfaces, outdoor exposed structures as well as for archaeological iron objects. Several methods are currently available for the stabilisation of this type of metallic substrate, however, none of them is completely efficient, and several relay on the use of hazardous compounds. In addition, especially for outdoor iron and pipelines structure a permanent protective treatment does not exist. After few years these corroded surfaces have to be re-treated and in some cases replaced. This causes substantial maintenance costs having an important economic impact on our society. Regarding archaeological iron objects, an additional issue has to be considered. In fact, each object consists of a unique testimony of our past that should be preserved and studied. An archaeological object is usually unique and if the conservation interventions fail, all the information that the object could have revealed will be lost. Scientists agree with the fact that until now an efficient and durable stabilisation treatment for corroded iron does not exist. As a consequence, there is a pressing need to investigate new approaches. To this purpose, the present thesis investigated the potential of microorganisms (bacteria and fungi) for the development of stabilisation methods for corroded iron. Since one of the main issues for this metal is chlorine, this study examined two different strategies of chlorine removal and conversion of the unstable iron compounds into more stable biogenic minerals. The first approach was an indirect chlorine extraction, consisting on the microbial removal of iron ions present in chlorinated corrosion compounds. For this purpose, microbial biogenic minerals production and fungal iron adsorption were investigated. In particular, exploiting biogenic minerals production of the strains TCE1 and LBE of the anaerobic bacterium Desulfitobacterium hafniense, it was possible to convert a part of the corrosion layer of corroded iron coupons, as well as of archaeological iron nails, into biogenic vivianite and magnetite. In addition, this study allowed definitely to assess that fungi are not the best candidates to develop stabilisation methods for corroded iron based on biogenic minerals production. In fact, even though Beauveria bassiana produced some biogenic crystals their amount was not sufficient for a precise characterisation, and none of the factors tested stimulated a higher production. Nevertheless, interesting results were obtained for fungal iron uptake. Indeed, iron uptake of the fungus Alternaria sp. was successfully used for a biocleaning of corroded iron coupons. In addition, another biotechnological application exploiting fungal iron uptake was investigated. In this study the ability of bacteria to use iron chelated in fungal dead biomass as a bioavailable source of iron was proved for Pseudomonas fluorescens. This could then be exploited to improve iron bioavailability, as well as availability of organic carbon in soil for other microbes and maybe also plants. A second approach regarding a direct method for the removal of chlorine was also studied. Uptake of potassium and chlorine was proved for B. bassiana that produced aggregates containing these elements onto its biomass when exposed to FeCl2. However this ability could not be further exploited, as chlorine uptake was not the main resistance mechanism used by this fungus against chlorine, and an efficient uptake of this ion was not measured. Finally, aiming to remove chlorine from corroded iron, volatiles organic compounds production was studied. Preliminary results showed that NaCl stimulates the production of particular compounds not present in absence of this substance. Overall it can be affirmed that this study allow to assess that microorganisms are a valuable alternative for the stabilisation of corroded iron. Bacteria could be employed to stabilize the corrosion layer by producing stable biogenic minerals, while fungi could be used for biocleaning of corroded iron.

scholarly journals DAP12 Inhibits Pulmonary Immune Responses to Cryptococcus neoformans

2016 ◽  
Vol 84 (6) ◽  
pp. 1879-1886 ◽  
Author(s):  
Lena J. Heung ◽  
Tobias M. Hohl
Keyword(s):  
Immune Response ◽  
Nk Cells ◽  
Cryptococcus Neoformans ◽  
Molecular Mechanisms ◽  
Content Type ◽  
Effector Cells ◽  
Opportunistic Fungal Pathogen ◽  
Efficient Uptake ◽  
Bacteria And Fungi

Cryptococcus neoformansis an opportunistic fungal pathogen that is inhaled into the lungs and can lead to life-threatening meningoencephalitis in immunocompromised patients. Currently, the molecular mechanisms that regulate the mammalian immune response to respiratory cryptococcal challenge remain poorly defined. DAP12, a signaling adapter for multiple pattern recognition receptors in myeloid and natural killer (NK) cells, has been shown to play both activating and inhibitory roles during lung infections by different bacteria and fungi. In this study, we demonstrate that DAP12 plays an important inhibitory role in the immune response toC. neoformans. Infectious outcomes in DAP12−/−mice, including survival and lung fungal burden, are significantly improved compared to those in C57BL/6 wild-type (WT) mice. We find that eosinophils and macrophages are decreased while NK cells are increased in the lungs of infected DAP12−/−mice. In contrast to WT NK cells, DAP12−/−NK cells are able to repressC. neoformansgrowthin vitro. Additionally, DAP12−/−macrophages are more highly activated than WT macrophages, with increased production of tumor necrosis factor (TNF) and CCL5/RANTES and more efficient uptake and killing ofC. neoformans. These findings suggest that DAP12 acts as a brake on the pulmonary immune response toC. neoformansby promoting pulmonary eosinophilia and by inhibiting the activation and antifungal activities of effector cells, including NK cells and macrophages.

scholarly journals Iron Bioavailability from Multiple Biofortified Foods Using an in Vitro Digestion, Caco-2 Assay for Optimizing a Cyclic Menu for a Randomized Efficacy Trial (P10-029-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Bryan Gannon ◽  
Raymond Glahn ◽  
Saurabh Mehta
Keyword(s):  
Sweet Potato ◽  
Pearl Millet ◽  
Iron Uptake ◽  
Matrix Effects ◽  
Iron Concentration ◽  
In Vitro Digestion ◽  
Iron Bioavailability ◽  
Effect Estimate ◽  
Freeze Dried

Abstract Objectives A multiple biofortified food crop trial targeting iron, zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is planned in India. We sought to determine iron bioavailability from biofortified and conventional crop mixes representative of planned meal components. Methods A 24-meal menu was developed based on pearl millet, sweet potato, and lentils targeted for a feeding trial. Crops were procured from India, cooked, and freeze-dried before two rounds of an established in vitro digestion/Caco-2 iron bioavailability assay. Samples used a fixed weight adjusted for sweet potato water content. Representative crop proportions were determined using k-means clustering, combined such that samples included either all biofortified or all control crop varieties, and analyzed in triplicate. Outcomes were Caco-2 iron uptake and uptake normalized to iron per sample for fractional bioavailability. Data were analyzed with generalized linear models in SAS accounting for crop proportions and variety. Results Across both experiments, biofortified pearl millet alone demonstrated higher iron uptake than conventional varieties (5.01 ± 1.66 vs. 2.17 ± 0.96 ng ferritin/mg protein, P ≤ 0.036). Addition of sweet potato to pearl millet did not change iron uptake for biofortified varieties (P ≥0.13), but increased control iron uptake for all amounts of sweet potato (P ≤ 0.006), which did not differ from biofortified varieties (P ≥ 0.08). Lentil proportion increased iron uptake (β = 4.6 ± 2.2, P = 0.009), with no effect of variety or a lentil by variety interaction (P ≥ 0.56). The overall effect estimate of biofortified vs. control was (β = 1.79 ± 0.91, P = 0.08). Iron uptake normalized to iron per sample was higher for control crops (P ≤ 0.02), and enhanced by sweet potato, while inhibited by pearl millet (both P < 0.001). Conclusions A Caco-2 assay predicts that biofortified pearl millet alone has greater iron bioavailability than control pearl millet. The addition of sweet potato and lentils increased overall and relative iron bioavailability, while reducing differences between biofortified and control varieties. Matrix effects, processing, and promoters/inhibitors of iron absorption should be considered in addition to total iron concentration when optimizing iron bioavailability. Funding Sources This work was supported by HarvestPlus and the USDA. Supporting Tables, Images and/or Graphs

Sucrosomial Iron®: A New Highly Bioavaible Oral Iron Supplement

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 4561-4561 ◽  
Author(s):  
Germano Tarantino ◽  
Elisa Brilli ◽  
Ylenia Zambito ◽  
Giulio Giordano ◽  
Francesco Equitani
Keyword(s):  
Iron Deficiency ◽  
Iron Uptake ◽  
Iron Bioavailability ◽  
Oral Iron ◽  
Deficiency Anemia ◽  
Sucrose Esters ◽  
Absorption Enhancers ◽  
Ferric Pyrophosphate ◽  
Ferritin Synthesis

Abstract Introduction: Iron deficiency is one of the most widespread nutritional deficiencies. Globally two billion people are suffering from iron- deficiency anemia (Hermida et al., 2010). Oral therapy for iron deficiency is mainly based on immediate release formulations of ferrous iron. However, modified formulations have been marketed to reduce gastrointestinal side effects and to prevent iron instability in the gastrointestinal tract. Overcoming biological barriers, including the gastrointestinal epithelial barriers, is a great challenge for pharmaceutical research and thus there is a need for new absorption enhancers with more favorable profile. Sucrose esters are widely used in the food industry, and there are reports on their potential use in pharmaceutical formulations as excipients (Szuts A et al., 2008). In vitro methods using cell cultures have been proposed to assess iron bioavailability as an alternative to in vivo methods. Caco-2 cells have shown numerous morphological and biochemical characteristics of enterocytes and have been successfully used to study iron absorption (Garcia et al., 1996; Jovani et al., 2001). Caco-2 monolayers formed a good barrier as reflected by high transepithelial resistance and positive immunostaining for junctional proteins. Sucrose esters in nontoxic concentrations significantly reduced resistance and impedance, and increased permeability of some components in Caco-2 monolayers. Recent data indicate that sucrose esters can enhance drug permeability through both the transcellular and paracellular routes (Kiss et al., 2014). Aim: The strong correlation between the published human absorption data and the iron uptake by Caco-2 cells makes them an ideal in vitro model to study iron bioavailability (Au and Reddy, 2000). For this, in the present study, we compared the bioavailability of innovative Oral Iron formulation based on Sucrosomial Iron¨ (Sideral¨) with three different Iron formulations (Figure 1). Materials and Methods: Sucrosomial Iron, preparation of ferric pyrophosphate convered by a phospholipids plus sucrose esters of fatty acids matrix; Lipofer¨, a water-dispersible micronised iron; Sunactive¨ ferric pyrophosphate, lecithin and emulsifiers. Results: The data showed that Sucrosomial Iron¨ (Sideral¨), is significantly more bioavaible than microencapsulated Ferric pyrophosphate ingredients, Lipofer¨ and Sunactive¨ and Ferrous Sulfate in Caco-2 cell model (Figure 1). Bibliography Au, A. P., Reddy, M. B. (2000). Caco-2 cells can be used to assess human iron bioavailability from a semipurified meal. J Nutr 130:1329-1334. Garcia et al. (1996). The Caco-2 cell culture system can be used as a model to study food iron availability. J Nutr 126:251-258. Hermida et al., Preparation and characterization of iron-containing liposomes: their effect on soluble iron uptake by Caco-2 cells Journal of Liposome Research, 2010, 1-10, Jovani et al. (2001) Calcium, iron, and zinc uptake from digests of infant formulas by Caco-2 cells. J Agric Food Chem 49:3480-3485. Kiss et al., (2014) Sucrose esters increase drug penetration, but do not inhibit p-glycoprotein in caco-2 intestinal epithelial cells J Pharm Sci. Oct;103(10):3107-19. Szuts A et al. (2008) Study of the effects of drugs on the structures of sucrose esters and the effects of solid-state interactions on drug release J Pharm Biomed Anal. 48: Figure 1. the graph shows the Ferritin levels of Caco-2 cells after iron formulations treatment. Sucrosomial Iron treated cells display significant increase of Ferritin synthesis compared to Lipofer and SunActive treated cells. Figure 1. the graph shows the Ferritin levels of Caco-2 cells after iron formulations treatment. Sucrosomial Iron treated cells display significant increase of Ferritin synthesis compared to Lipofer and SunActive treated cells. Disclosures Tarantino: Pharmanutra s.p.a.: Employment. Brilli:Pharmanutra s.p.a.: Employment.

scholarly journals StreptomycesVolatile Compounds Influence Exploration and Microbial Community Dynamics by Altering Iron Availability

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Stephanie E. Jones ◽  
Christine A. Pham ◽  
Matthew P. Zambri ◽  
Joseph McKillip ◽  
Erin E. Carlson ◽  
...  
Keyword(s):  
Microbial Community ◽  
Nutrient Availability ◽  
Iron Uptake ◽  
Community Dynamics ◽  
Critical Role ◽  
Iron Availability ◽  
Interspecies Interactions ◽  
Community Interactions ◽  
Content Type ◽  
Bacteria And Fungi

ABSTRACTBacteria and fungi produce a wide array of volatile organic compounds (VOCs), and these can act as chemical cues or as competitive tools. Recent work has shown that the VOC trimethylamine (TMA) can promote a new form ofStreptomycesgrowth, termed “exploration.” Here, we report that TMA also serves to alter nutrient availability in the area surrounding exploring cultures: TMA dramatically increases the environmental pH and, in doing so, reduces iron availability. This, in turn, compromises the growth of other soil bacteria and fungi. In response to this low-iron environment,Streptomyces venezuelaesecretes a suite of differentially modified siderophores and upregulates genes associated with siderophore uptake. Further reducing iron levels by limiting siderophore uptake or growing cultures in the presence of iron chelators enhanced exploration. Exploration was also increased whenS. venezuelaewas grown in association with the related low-iron- and TMA-tolerantAmycolatopsisbacteria, due to competition for available iron. We are only beginning to appreciate the role of VOCs in natural communities. This work reveals a new role for VOCs in modulating iron levels in the environment and implies a critical role for VOCs in modulating the behavior of microbes and the makeup of their communities. It further adds a new dimension to our understanding of the interspecies interactions that influenceStreptomycesexploration and highlights the importance of iron in exploration modulation.IMPORTANCEMicrobial growth and community interactions are influenced by a multitude of factors. A new mode ofStreptomycesgrowth—exploration—is promoted by interactions with the yeastSaccharomycescerevisiaeand requires the emission of trimethylamine (TMA), a pH-raising volatile compound. We show here that TMA emission also profoundly alters the environment around exploring cultures. It specifically reduces iron availability, and this in turn adversely affects the viability of surrounding microbes. Paradoxically,Streptomycesbacteria thrive in these iron-depleted niches, both rewiring their gene expression and metabolism to facilitate iron uptake and increasing their exploration rate. Growth in close proximity to other microbes adept at iron uptake also enhances exploration. Collectively, the data from this work reveal a new role for bacterial volatile compounds in modulating nutrient availability and microbial community behavior. The results further expand the repertoire of interspecies interactions and nutrient cues that impactStreptomycesexploration and provide new mechanistic insight into this unique mode of bacterial growth.

scholarly journals Reduction-dependent siderophore assimilation in a model pennate diatom

2019 ◽  
Vol 116 (47) ◽  
pp. 23609-23617 ◽  
Author(s):  
Tyler H. Coale ◽  
Mark Moosburner ◽  
Aleš Horák ◽  
Miroslav Oborník ◽  
Katherine A. Barbeau ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Iron Acquisition ◽  
Close Association ◽  
Iron Bioavailability ◽  
Trophic Levels ◽  
Receptor Protein ◽  
Pennate Diatom ◽  
Surface Ocean ◽  
Specific Proteins ◽  
Genetic Techniques

Iron uptake by diatoms is a biochemical process with global biogeochemical implications. In large regions of the surface ocean diatoms are both responsible for the majority of primary production and frequently experiencing iron limitation of growth. The strategies used by these phytoplankton to extract iron from seawater constrain carbon flux into higher trophic levels and sequestration into sediments. In this study we use reverse genetic techniques to target putative iron-acquisition genes in the model pennate diatom Phaeodactylum tricornutum. We describe components of a reduction-dependent siderophore acquisition pathway that relies on a bacterial-derived receptor protein and provides a viable alternative to inorganic iron uptake under certain conditions. This form of iron uptake entails a close association between diatoms and siderophore-producing organisms during low-iron conditions. Homologs of these proteins are found distributed across diatom lineages, suggesting the significance of siderophore utilization by diatoms in the marine environment. Evaluation of specific proteins enables us to confirm independent iron-acquisition pathways in diatoms and characterize their preferred substrates. These findings refine our mechanistic understanding of the multiple iron-uptake systems used by diatoms and help us better predict the influence of iron speciation on taxa-specific iron bioavailability.

scholarly journals Use of Bacteria To Stabilize Archaeological Iron

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Lucrezia Comensoli ◽  
Julien Maillard ◽  
Monica Albini ◽  
Frederic Sandoz ◽  
Pilar Junier ◽  
...  
Keyword(s):  
Iron Age ◽  
Iron Reduction ◽  
Physical Stability ◽  
Corrosion Layer ◽  
Homogeneous Layer ◽  
Waste Products ◽  
Promising Alternative ◽  
Content Type ◽  
Archaeological Iron ◽  
Archaeological Objects

ABSTRACT Iron artifacts are common among the findings of archaeological excavations. The corrosion layer formed on these objects requires stabilization after their recovery, without which the destruction of the item due to physicochemical damage is likely. Current technologies for stabilizing the corrosion layer are lengthy and generate hazardous waste products. Therefore, there is a pressing need for an alternative method for stabilizing the corrosion layer on iron objects. The aim of this study was to evaluate an alternative conservation-restoration method using bacteria. For this, anaerobic iron reduction leading to the formation of stable iron minerals in the presence of chlorine was investigated for two strains of Desulfitobacterium hafniense (strains TCE1 and LBE). Iron reduction was observed for soluble Fe(III) phases as well as for akaganeite, the most troublesome iron compound in the corrosion layer of archaeological iron objects. In terms of biogenic mineral production, differential efficiencies were observed in assays performed on corroded iron coupons. Strain TCE1 produced a homogeneous layer of vivianite covering 80% of the corroded surface, while on the coupons treated with strain LBE, only 10% of the surface was covered by the same mineral. Finally, an attempt to reduce iron on archaeological objects was performed with strain TCE1, which led to the formation of both biogenic vivianite and magnetite on the surface of the artifacts. These results demonstrate the potential of this biological treatment for stabilizing archaeological iron as a promising alternative to traditional conservation-restoration methods. IMPORTANCE Since the Iron Age, iron has been a fundamental material for the building of objects used in everyday life. However, due to its reactivity, iron can be easily corroded, and the physical stability of the object built is at risk. This is particularly true for archaeological objects on which a potentially unstable corrosion layer is formed during the time the object is buried. After excavation, changes in environmental conditions (e.g., higher oxygen concentration or lower humidity) alter the stability of the corrosion layer and can lead to the total destruction of the object. In this study, we demonstrate the feasibility of an innovative treatment based on bacterial iron reduction and biogenic mineral formation to stabilize the corrosion layer and protect these objects.

The Use of Caco-2 Cells to Estimate Fe Absorption in Humans - a Critical Appraisal

2010 ◽  
Vol 80 (45) ◽  
pp. 307-313 ◽  
Author(s):  
Ann-Sofie Sandberg
Keyword(s):  
Iron Uptake ◽  
Iron Absorption ◽  
Cell Model ◽  
Iron Bioavailability ◽  
Dietary Factors ◽  
Cell Uptake ◽  
Epithelial Cell Line ◽  
Cellular Iron ◽  
Cellular Iron Uptake

The Caco-2 cell model is widely used to assess the bioaccessibility/availability of iron from foods and diets. Analysis of iron uptake in this human epithelial cell line is usually preceded by a two-step digestion to simulate the conditions in the stomach and small intestine. Moreover, culturing the cells on inserts permits the measurement of iron transport. The cellular iron uptake is determined by direct measurements using radioisotopes, or indirectly by measurement of ferritin, the intracellular storage form of iron. There is a good correlation between Caco-2 cell uptake and human iron bioavailability for a number of dietary factors known to affect iron absorption. However, recent data suggest that in some cases there is no correlation. Possible reasons for such discrepancies, the benefits, and limitations of the Caco-2 cell model are discussed. In conclusion, in vitro experiments with Caco-2 cells are important tools for ranking foods with respect to bioavailability, for mechanistic studies of iron absorption, and for studies of dietary factors influencing absorption. The results need to be confirmed in humans.

scholarly journals Iron Bioavailability from Multiple Biofortified Foods Using an In Vitro Digestion, Caco-2 Assay for Optimizing a Cyclical Menu for a Randomized Efficacy Trial

2021 ◽  
Vol 5 (9) ◽  
Author(s):  
Bryan M Gannon ◽  
Raymond P Glahn ◽  
Saurabh Mehta
Keyword(s):  
Sweet Potato ◽  
Iron Uptake ◽  
Matrix Effects ◽  
Human Study ◽  
In Vitro Digestion ◽  
Iron Bioavailability ◽  
Total Iron ◽  
Cell Protein ◽  
Freeze Dried

ABSTRACT Background Inadequate nutritional status contributes to substantial losses in human health and productivity globally. A multiple biofortified food crop trial targeting iron, zinc, and vitamin A deficiencies among young children and their breastfeeding mothers is being conducted in India. Objective We sought to determine the relative iron bioavailability from biofortified and conventional crops and crop combinations representative of a cyclical menu using crops targeted for inclusion in the feeding trial. Methods Crops were procured from India, cooked, freeze-dried, and analyzed with an established in vitro digestion/Caco-2 iron bioavailability assay using a fixed sample weight. Crop proportions representative of meals planned for the human study were determined and combined such that samples included either all biofortified or all control crops. Crops were analyzed as single crops (n = 4) or crop combinations (n = 7) by variety (biofortified or control) in triplicate. The primary outcome was iron uptake measured by Caco-2 ferritin production normalized to total Caco-2 protein (nanograms of ferritin/milligrams of cell protein) analyzed for effects of crop variety and crop proportion using generalized linear models. Results Biofortified pearl millet alone demonstrated higher iron uptake than conventional varieties (5.01 ± 1.66 vs. 2.17 ± 0.96; P = 0.036). Addition of sweet potato or sweet potato + pulse improved iron uptake for all proportions tested in control varieties and select proportions for biofortified varieties (P ≤ 0.05). Two multiple crop combinations demonstrated modestly higher iron uptake from biofortified crops. Conclusions Optimizing total iron delivery should consider matrix effects, processing, and promoters/inhibitors of iron absorption in addition to total iron concentration. Future directions include evaluating recipes as prepared for consumption and comparison against human iron bioavailability studies.

scholarly journals Iron Pathways and Iron Chelation Approaches in Viral, Microbial, and Fungal Infections

2020 ◽  
Vol 13 (10) ◽  
pp. 275
Author(s):  
Ravneet Chhabra ◽  
Aishwarya Saha ◽  
Ashkon Chamani ◽  
Nicole Schneider ◽  
Riya Shah ◽  
...  
Keyword(s):  
Iron Uptake ◽  
Fungal Infections ◽  
Iron Acquisition ◽  
Iron Chelation ◽  
Essential Element ◽  
Iron Availability ◽  
Tight Control ◽  
Potential Clinical Benefit ◽  
Bacteria And Fungi ◽  
Spread Of Infection

Iron is an essential element required to support the health of organisms. This element is critical for regulating the activities of cellular enzymes including those involved in cellular metabolism and DNA replication. Mechanisms that underlie the tight control of iron levels are crucial in mediating the interaction between microorganisms and their host and hence, the spread of infection. Microorganisms including viruses, bacteria, and fungi have differing iron acquisition/utilization mechanisms to support their ability to acquire/use iron (e.g., from free iron and heme). These pathways of iron uptake are associated with promoting their growth and virulence and consequently, their pathogenicity. Thus, controlling microorganismal survival by limiting iron availability may prove feasible through the use of agents targeting their iron uptake pathways and/or use of iron chelators as a means to hinder development of infections. This review will serve to assimilate findings regarding iron and the pathogenicity of specific microorganisms, and furthermore, find whether treating infections mediated by such organisms via iron chelation approaches may have potential clinical benefit.

Natural glufosinate resistance of soil microorganisms and GMO safety

2010 ◽  
Vol 5 (5) ◽  
pp. 656-663 ◽  
Author(s):  
Timea Tothova ◽  
Anna Sobekova ◽  
Katarina Holovska ◽  
Jaroslav Legath ◽  
Peter Pristas ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Soil Microorganisms ◽  
Bacillus Pumilus ◽  
Resistance Mechanism ◽  
Plate Count ◽  
Bar Gene ◽  
Soil Microcosms ◽  
Plate Count Method ◽  
Bacterium Bacillus ◽  
Bacteria And Fungi

AbstractBacteria and fungi from pristine soil, never exposed to glufosinate herbicide, were isolated and analyzed for glufosinate tolerance. Seven of the 15 tested isolates were sensitive to 1 mM glufosinate (an active ingredient of many nonselective contact herbicides), 5 were resistant to 4 mM glufosinate and 3 even to 8 mM glufosinate in liquid medium. None of the isolated microorganisms carried the gene for glufosinate resistance bar (bialaphos resistance) in its genome and at least in some of glufosinate-resistant isolates the increased glutamine synthetase level was detected as a possible resistance mechanism. The transfer of the bar glufosinate resistance gene from transgenic maize Bt 176 into glufosinate-sensitive soil bacterium Bacillus pumilus S1 was not detected under the laboratory conditions by a classical plate count method and PCR. The ecological risk of potential bar gene transfer from genetically modified plants into soil microcosms under natural circumstances is discussed.

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