Quantitation and localisation of (in vitro) transglutaminase-catalysed glutamine hydroxylation using mass spectrometry

NARCIS (Netherlands)

Piersma, S.R.; Pijpekamp, A. van de; Wijngaards, G.; Gruppen, H.; Boumans, H.

2002-01-01

A mass spectrometric approach was chosen to quantify and localise in vitro enzymatically modified glutamine (Gln) residues in a glutamine-rich protein. This protein (named dB1), a cloned domain of the high molecular weight wheat glutenin subunit Dx5, was modified by microbial transglutaminase

Microbial transglutaminase : a review of its production and application in food processing

NARCIS (Netherlands)

Zhu, Y.; Rinzema, A.; Tramper, J.; Bol, J.

1995-01-01

Transglutaminase (EC 2.3.2.13) catalyses an acyl-transfer reaction in which the γ-carboxamide groups of peptide-bound glutaminyl residues are the acyl donors. The enzyme catalyses in vitro cross-linking in whey proteins, soya proteins, wheat proteins, beef myosin, casein and crude actomyosin refined

Evaluation of the potential allergenicity of the enzyme microbial transglutaminase using the 2001 FAO/WHO Decision Tree

DEFF Research Database (Denmark)

Pedersen, Mona H.; Hansen, Tine K.; Sten, Eva

2004-01-01

All novel proteins must be assessed for their potential allergenicity before they are introduced into the food market. One method to achieve this is the 2001 FAO/WHO Decision Tree recommended for evaluation of proteins from genetically modified organisms (GMOs). It was the aim of this study...... to investigate the allergenicity of microbial transglutaminase (m-TG) from Streptoverticillium mobaraense. Amino acid sequence similarity to known allergens, pepsin resistance, and detection of protein binding to specific serum immunoglobulin E (IgE) (RAST) have been evaluated as recommended by the decision tree...... meets the requirements of the decision tree. However, there is a match at the five contiguous amino acid level to the major codfish allergen Gad c1. The potential cross reactivity between m-TG and Gad c1 was investigated in RAST using sera from 25 documented cod-allergic patients and an extract of raw...

Pathogen entrapment by transglutaminase--a conserved early innate immune mechanism.

Directory of Open Access Journals (Sweden)

Zhi Wang

2010-02-01

Full Text Available Clotting systems are required in almost all animals to prevent loss of body fluids after injury. Here, we show that despite the risks associated with its systemic activation, clotting is a hitherto little appreciated branch of the immune system. We compared clotting of human blood and insect hemolymph to study the best-conserved component of clotting systems, namely the Drosophila enzyme transglutaminase and its vertebrate homologue Factor XIIIa. Using labelled artificial substrates we observe that transglutaminase activity from both Drosophila hemolymph and human blood accumulates on microbial surfaces, leading to their sequestration into the clot. Using both a human and a natural insect pathogen we provide functional proof for an immune function for transglutaminase (TG. Drosophila larvae with reduced TG levels show increased mortality after septic injury. The same larvae are also more susceptible to a natural infection involving entomopathogenic nematodes and their symbiotic bacteria while neither phagocytosis, phenoloxidase or-as previously shown-the Toll or imd pathway contribute to immunity. These results firmly establish the hemolymph/blood clot as an important effector of early innate immunity, which helps to prevent septic infections. These findings will help to guide further strategies to reduce the damaging effects of clotting and enhance its beneficial contribution to immune reactions.

Microbial Transglutaminase Used in Bread Preparation at Standard Bakery Concentrations Does Not Increase Immunodetectable Amounts of Deamidated Gliadin.

Science.gov (United States)

Heil, Andreas; Ohsam, Jürgen; van Genugten, Bernard; Diez, Oscar; Yokoyama, Keiichi; Kumazawa, Yoshiyuki; Pasternack, Ralf; Hils, Martin

2017-08-16

The effect of standard bakery concentrations of microbial transglutaminase (MTG) in wheat bread preparation on the immunoreactivity of sera of celiac disease (CD) patients was investigated. Immunoblotting using monoclonal antibodies specific to unmodified and/or deamidated gliadin showed no differences between control bread and MTG bread. Deamidation of gliadin could not be detected at standard MTG concentrations. Sera of CD patients were characterized using anti-gliadin and anti-deamidated gliadin peptide (DGP) enzyme-linked immunosorbent assay and grouped into DGP high- and low-titer pools. The recognition pattern obtained after using both CD sera pools for immunoblotting did not reveal differences between control and MTG-treated bread protein extracts. Our results indicate that MTG treatment of wheat bread prepared with typical MTG concentrations used in standard bakery processes does not lead to immunodetectable amounts of CD immunotoxic deamidated gliadins.

Effect of Microbial Transglutaminase on Ice Cream Heat Resistance Properties – a Short Report

Directory of Open Access Journals (Sweden)

Kasprzyk Iwona

2016-07-01

Full Text Available The objective of this study was to investigate the effect of the addition of transglutaminase (TG preparation Saprovia L ® (PMT TRADING Co. Ltd, Lodz, Poland on the properties of ice cream with 40 g/kg and 70 g/kg fat content. TG was added at a concentration of 2 U/g protein. We studied the effect of transglutaminase on fresh and 3-month-stored at -25°C ice cream. Ice cream mixes were prepared with 5 g/kg stabilizer. Melting test was performed after thermal shocks until the “1st drop” occurrence. The amount of effluent was measured within the 0-120 min time frame. We evaluated the appearance of the samples and carried out the TPA and compression analysis. The addition of the enzyme has increased the resistance of stored ice cream to repeated thermal shocks.

Microbial transglutaminase treatment in pasta-production does not affect the immunoreactivity of gliadin with celiac disease patients' sera.

Science.gov (United States)

Ruh, Tobias; Ohsam, Jürgen; Pasternack, Ralf; Yokoyama, Keiichi; Kumazawa, Yoshiyuki; Hils, Martin

2014-07-30

The effect of microbial transglutaminase (MTG)-treatment of pasta-dough on the immunoreactivity with celiac disease patient's sera has been investigated. Modification by MTG has been proven by determination of the MTG reaction product ε-(γ-glutamyl)lysine (3.63 μmol/g protein), which was not detectable in non-MTG-treated pasta. Antigenicity has been analyzed by immunoblotting and ELISA using gliadin-extracts from pasta and MTG-treated pasta. Immunoblotting showed that the antibody-population (antigliadin antibodies and antideamidated gliadin antibodies) of the sera is specific for every individual patient. Immunoblotting and ELISA showed that there is no difference in immunoreactivity of gliadin extracted from pasta and MTG-pasta. Recognition pattern and intensity in Western blot as well as antibody titer has also been identical even for sera with a high antideamidated gliadin antibody titer. These results indicate no difference between pasta-gliadin and MTG-pasta-gliadin and especially no increased deamidation in pasta-gliadin by MTG-treatment.

Emulsion properties of pork myofibrillar protein in combination with microbial transglutaminase and calcium alginate under various pH conditions.

Science.gov (United States)

Hong, Geun Pyo; Min, Sang-Gi; Chin, Koo Bok

2012-01-01

In this study, the effects of microbial transglutaminase (MTG) and calcium alginate (CA) systems in combination with soybean oil on the emulsion properties of porcine myofibrillar protein (MP) were evaluated under various pH conditions. MTG was shown to improve emulsifying capacity and creaming stability, which increased with increasing pH values up to 6.5. The CA did not influence emulsifying capacity, but it improved the creaming stability of the MP-stabilized emulsions. Both MTG and CA enhanced the rheological properties, but their effects on the physical characteristics of the protein evidenced an opposite trend in relation to pH, i.e., the MTG system improved both the emulsion and gelling properties with increasing pH, whereas the CA system was effective when the pH was lowered. By combining the two MP gelling systems, a stable and pH-insensible emulsion could be produced. Copyright © 2011 Elsevier Ltd. All rights reserved.

Exogenous transglutaminase improves multiple-stress tolerance in Lactococcus lactis and other lactic acid bacteria with glutamine and lysine in the cell wall.

Science.gov (United States)

Li, Yu; Kan, Zhipeng; You, Yuanli; Gao, Xueling; Wang, Zhigeng; Fu, Ruiyan

2015-12-01

To increase the resistance of ingested bacteria to multiple environmental stresses, the role of transglutaminase in Lactococcus lactis and possible mechanisms of action were explored. L. lactis grown with transglutaminase exhibited significantly higher resistance to bile salts, stimulated gastric juice, antibiotics, NaCl, and cold stress compared to the control (cultured without transglutaminase), with no negative influence on cell growth. Transmission electron microscopy revealed that the cell walls of L. lactis cultured with 9 U transglutaminase/ml were approx. 1.9-times thicker than the control. Further analysis demonstrated that the multi-resistant phenotype was strain-specific; that is, it occurred in bacteria with the presence of glutamine and lysine in the peptidoglycan. Supplementation of culture media with transglutaminase is an effective, simple, and inexpensive strategy to protect specific ingested bacteria against multiple environmental challenges.

In vitro gastrointestinal digestion study of a novel bio-tofu with special emphasis on the impact of microbial transglutaminase

Directory of Open Access Journals (Sweden)

Guangliang Xing

2016-12-01

Full Text Available We have developed a novel bio-tofu, made from mixed soy and cow milk (MSCM, using Lactobacillus helveticus MB2-1 and Lactobacillus plantarum B1-6 incorporated with microbial transglutaminase (MTGase as coagulant. MTGase was added to improve the textural properties and suit for cooking. However, the effect of MTGase on the digestion of mixed-protein fermented by lactic acid bacteria was unclear. This study aimed at evaluating the effect of MTGase on protein digestion of bio-tofu under simulated gastrointestinal digestion condition. The results showed that addition of MTGase could affect the particle size distribution, degree of hydrolysis, the content of soluble proteins and free amino acids. Based on the electrophoresis data, MTGase addition enhanced protein polymerization. During gastric and intestinal digestion process, proteins from bio-tofu were degraded into low molecular mass peptides. Our results suggested that incorporation of MTGase could lead to enzymatic modification of proteins of bio-tofu which may help in controlling energy intake and decrease the chance of food allergy.

In vitro gastrointestinal digestion study of a novel bio-tofu with special emphasis on the impact of microbial transglutaminase

Science.gov (United States)

Xing, Guangliang; Rui, Xin; Jiang, Mei; Xiao, Yu; Guan, Ying; Wang, Dan

2016-01-01

We have developed a novel bio-tofu, made from mixed soy and cow milk (MSCM), using Lactobacillus helveticus MB2-1 and Lactobacillus plantarum B1-6 incorporated with microbial transglutaminase (MTGase) as coagulant. MTGase was added to improve the textural properties and suit for cooking. However, the effect of MTGase on the digestion of mixed-protein fermented by lactic acid bacteria was unclear. This study aimed at evaluating the effect of MTGase on protein digestion of bio-tofu under simulated gastrointestinal digestion condition. The results showed that addition of MTGase could affect the particle size distribution, degree of hydrolysis, the content of soluble proteins and free amino acids. Based on the electrophoresis data, MTGase addition enhanced protein polymerization. During gastric and intestinal digestion process, proteins from bio-tofu were degraded into low molecular mass peptides. Our results suggested that incorporation of MTGase could lead to enzymatic modification of proteins of bio-tofu which may help in controlling energy intake and decrease the chance of food allergy. PMID:27994970

Raw-appearing Restructured fish models made with Sodium alginate or Microbial transglutaminase and effect of chilled storage Reestrutura do modelo peixe feito com transglutaminase alginato de sódio e microbiana e o efeito do armazenamento refrigerado

Directory of Open Access Journals (Sweden)

Helena Moreno

2013-03-01

Full Text Available Restructuring by adding Sodium Alginate or Microbial Transglutaminase (MTGase using cold gelation technology make it possible to obtain many different raw products from minced and/or chopped fish muscle that are suitable for being used as the basis of new restructured products with different physicochemical properties and even different compositions. Special consideration must be given to their shelf-life and the changes that may take place during chilling, both in visual appearance and physicochemical properties. After chilled storage, the restructured models made with different muscular particle size and composition at low temperature (5 °C, it was observed that microbial growth limited the shelf-life to 7-14 days. Mechanical properties increased (p 0.05 was detected during storage.A reestruturação pela adição de Alginato de sódio ou Transglutaminase microbiana (MTGase utilizando a tecnologia de gelificação pelo frio torna possível a obtenção de diversos produtos crus, a partir de músculo de peixe picado, que são apropriados para serem usados como base de novos produtos reestruturados com diferentes propriedades físico-químicas e até com composições diferentes. Consideração especial deve ser dada ao prazo de validade e às mudanças que podem ocorrer durante a refrigeração, tanto no aspecto visual como nas propriedades físico-químicas. Após o armazenamento refrigerado de modelos reestruturados feitos com diferentes tamanhos de partículas musculares e composições a baixas temperaturas (5 °C, foi observado um crescimento microbiano que limita o prazo de validade para 7 a 14 dias. As propriedades mecânicas aumentaram (p < 0,05 durante o tempo, e os valores mais altos foram mais observados nas amostras elaboradas unindo partículas de músculo de tamanho pequeno do que nas elaboradas por homogeneização. O rendimento após cozimento e a perda de purga não apresentaram uma evolução clara nem foi detectada qualquer

Recent advances in the application of microbial transglutaminase crosslinking in cheese and ice cream products: A review.

Science.gov (United States)

Taghi Gharibzahedi, Seyed Mohammad; Koubaa, Mohamed; Barba, Francisco J; Greiner, Ralf; George, Saji; Roohinejad, Shahin

2018-02-01

Microbial transglutaminase (MTGase) has been currently utilized to form new food structures and matrices with high physicochemical stability. Incorporation of this multi-functional enzyme into structural composition of milk protein-based products, such as cheese and ice cream, can not only be a successful strategy to improve their nutritional and technological characteristics through intramolecular cross-linking, but also to reduce the production cost by decreasing fat and stabilizer contents. The recent research developments and promising results of MTGase application in producing functional formulations of cheese and ice cream with higher quality characteristics are reviewed. New interesting insights and future perspectives are also presented. The addition of MTGase to cheese led to significant improvements in moisture, yield, texture, rheology and sensory properties, without changes in the chemical composition. Furthermore, pH value of ice cream is not affected by the MTGase treatment. Compared to untreated ice creams, application of MTGase significantly promotes consistency, fat destabilization, overrun and organoleptic acceptance, while a substantial reduction in firmness and melting rate of samples was observed. The addition of MTGase to cheese and ice cream-milk provides reinforcement to the protein matrix and can be considered as a novel additive for improving the physicochemical and organoleptic properties of final products. Copyright © 2017 Elsevier B.V. All rights reserved.

Biotechnological Aspects of Microbial Extracellular Electron Transfer

Science.gov (United States)

Kato, Souichiro

2015-01-01

Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

A sensitive HPLC-MS/MS method for the simultaneous detection of microbial transglutaminase, and bovine and porcine fibrinogen/thrombin in restructured meat.

Science.gov (United States)

Jira, Wolfgang; Schwägele, Fredi

2017-12-15

A sensitive HPLC-MS/MS method for the simultaneous detection of microbial transglutaminase (TG) from Streptomyces mobaraensis, and bovine and porcine fibrinogen/thrombin in restructured meat was developed using tryptic marker peptides of TG (five markers), and bovine and porcine fibrinogen (six markers each). Meat binding experiments with beef and pork were performed using a technical TG mixture (Activa, Ajinomoto), and bovine and porcine plasmapowder FG (PPFG; Sonac B.V.). The method developed allows the simultaneous detection of the use of these cold-set binders in raw and heated samples. The peak areas of the fibrinogen marker peptides were increased by a factor of about 100, compared to blank values originating from the occurrence of residual blood in meat, using a concentration of 0.6% bovine and porcine PPFG. A differentiation between the use of blood plasma powder and PPFG using the ratios of fibrinogen to serotransferrin peptide peak areas seems to be possible. Copyright © 2017 Elsevier Ltd. All rights reserved.

Transglutaminase inhibitor from milk

NARCIS (Netherlands)

Jong, G.A.H. de; Wijngaards, G.; Koppelman, S.J.

2003-01-01

Cross-linking experiments of skimmed bovine milk with bacterial transglutaminase isolated from Streptoverticillium mobaraense showed only some degree of formation of high-molecular-weight casein polymers. Studies on the nature of this phenomenon revealed that bovine milk contains an inhibitor of

Transglutaminase induction by various cell death and apoptosis pathways.

Science.gov (United States)

Fesus, L; Madi, A; Balajthy, Z; Nemes, Z; Szondy, Z

1996-10-31

Clarification of the molecular details of forms of natural cell death, including apoptosis, has become one of the most challenging issues of contemporary biomedical sciences. One of the effector elements of various cell death pathways is the covalent cross-linking of cellular proteins by transglutaminases. This review will discuss the accumulating data related to the induction and regulation of these enzymes, particularly of tissue type transglutaminase, in the molecular program of cell death. A wide range of signalling pathways can lead to the parallel induction of apoptosis and transglutaminase, providing a handle for better understanding the exact molecular interactions responsible for the mechanism of regulated cell death.

Engineered, highly reactive substrates of microbial transglutaminase enable protein labeling within various secondary structure elements.

Science.gov (United States)

Rachel, Natalie M; Quaglia, Daniela; Lévesque, Éric; Charette, André B; Pelletier, Joelle N

2017-11-01

Microbial transglutaminase (MTG) is a practical tool to enzymatically form isopeptide bonds between peptide or protein substrates. This natural approach to crosslinking the side-chains of reactive glutamine and lysine residues is solidly rooted in food and textile processing. More recently, MTG's tolerance for various primary amines in lieu of lysine have revealed its potential for site-specific protein labeling with aminated compounds, including fluorophores. Importantly, MTG can label glutamines at accessible positions in the body of a target protein, setting it apart from most labeling enzymes that react exclusively at protein termini. To expand its applicability as a labeling tool, we engineered the B1 domain of Protein G (GB1) to probe the selectivity and enhance the reactivity of MTG toward its glutamine substrate. We built a GB1 library where each variant contained a single glutamine at positions covering all secondary structure elements. The most reactive and selective variants displayed a >100-fold increase in incorporation of a recently developed aminated benzo[a]imidazo[2,1,5-cd]indolizine-type fluorophore, relative to native GB1. None of the variants were destabilized. Our results demonstrate that MTG can react readily with glutamines in α-helical, β-sheet, and unstructured loop elements and does not favor one type of secondary structure. Introducing point mutations within MTG's active site further increased reactivity toward the most reactive substrate variant, I6Q-GB1, enhancing MTG's capacity to fluorescently label an engineered, highly reactive glutamine substrate. This work demonstrates that MTG-reactive glutamines can be readily introduced into a protein domain for fluorescent labeling. © 2017 The Protein Society.

Possible Role of the Transglutaminases in the Pathogenesis of Alzheimer's Disease and Other Neurodegenerative Diseases

Directory of Open Access Journals (Sweden)

Antonio Martin

2011-01-01

Full Text Available Transglutaminases are ubiquitous enzymes which catalyze posttranslational modifications of proteins. Recently, transglutaminase-catalyzed post-translational modification of proteins has been shown to be involved in the molecular mechanisms responsible for human diseases. Transglutaminase activity has been hypothesized to be involved also in the pathogenetic mechanisms responsible for several human neurodegenerative diseases. Alzheimer's disease and other neurodegenerative diseases, such as Parkinson's disease, supranuclear palsy, Huntington's disease, and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This paper focuses on the possible molecular mechanisms by which transglutaminase activity could be involved in the pathogenesis of Alzheimer's disease and other neurodegenerative diseases, and on the possible therapeutic effects of selective transglutaminase inhibitors for the cure of patients with diseases characterized by aberrant transglutaminase activity.

Exocellular electron transfer in anaerobic microbial communities.

Science.gov (United States)

Stams, Alfons J M; de Bok, Frank A M; Plugge, Caroline M; van Eekert, Miriam H A; Dolfing, Jan; Schraa, Gosse

2006-03-01

Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory syntrophic consortia of proton-reducing acetogenic bacteria and hydrogen-consuming methanogenic archaea. Anaerobic microorganisms that use insoluble electron acceptors for growth, such as iron- and manganese-oxide as well as inert graphite electrodes in microbial fuel cells, also transfer electrons exocellularly. Soluble compounds, like humic substances, quinones, phenazines and riboflavin, can function as exocellular electron mediators enhancing this type of anaerobic respiration. However, direct electron transfer by cell-cell contact is important as well. This review addresses the mechanisms of exocellular electron transfer in anaerobic microbial communities. There are fundamental differences but also similarities between electron transfer to another microorganism or to an insoluble electron acceptor. The physical separation of the electron donor and electron acceptor metabolism allows energy conservation in compounds as methane and hydrogen or as electricity. Furthermore, this separation is essential in the donation or acceptance of electrons in some environmental technological processes, e.g. soil remediation, wastewater purification and corrosion.

Tgm1-like transglutaminases in tilapia (Oreochromis mossambicus.

Directory of Open Access Journals (Sweden)

Sandra I Rodriguez Cruz

Full Text Available Among the adaptations of aquatic species during evolution of terrestrial tetrapods was the development of an epidermis preventing desiccation. In present day mammals, keratinocytes of the epidermis, using a membrane-bound transglutaminase (Tgm1, accomplish this function by synthesizing a scaffold of cross-linked protein to which a lipid envelope is attached. This study characterizes the abilities of two homologous transglutaminase isozymes in the teleost fish tilapia to form cross-linked protein structures and their expression in certain tissues. Results indicate they are capable of membrane localization and of generating cellular structures resistant to detergent solubilization. They are both expressed in epithelial cells of the lip, buccal cavity and tips of gill filaments. Adaptation of transglutaminase use in evolution of terrestrial keratinocytes evidently involved refinements in tissue expression, access to suitable substrate proteins and activation of cross-linking during terminal differentiation.

Possible roles of transglutaminases in molecular mechanisms responsible for human neurodegenerative diseases

Directory of Open Access Journals (Sweden)

Nicola Gaetano Gatta

2016-11-01

Full Text Available Transglutaminases are a family of Ca2+-dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted/crosslinked adducts or –OH groups (to form ester linkages. In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for human autoimmune diseases, Celiac Disease is just one of them. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. This review describes the possible molecular mechanisms by which these enzymes could be responsible for such diseases and the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Role of transglutaminase in insulin release. Study with glycine and sarcosine methylesters

International Nuclear Information System (INIS)

Sener, A.; Dunlop, M.E.; Gomis, R.; Mathias, P.C.; Malaisse-Lagae, F.; Malaisse, W.J.

1985-01-01

The Ca2+-responsive enzyme transglutaminase, which catalyzes the cross-bridging of proteins, is present in pancreatic islet cells, but its participation in the process of insulin release remains to be documented. Glycine methylester (1.0-10.0 mM) inhibited, in a dose-related manner, transglutaminase activity in rat pancreatic islet homogenates, decreased [ 14 C]methylamine incorporation into endogenous proteins of intact islets, and caused a rapid and reversible inhibition of insulin release evoked by D-glucose, while failing to affect D-[U- 14 C]glucose oxidation. Glycine methylester also inhibited insulin release induced by other nutrient or nonnutrient secretagogues. Sarcosine methylester failed to affect transglutaminase activity, [ 14 C]methylamine incorporation, and insulin release. Both methylesters mobilized 45 Ca from prelabeled intact islets, from membranes of islet cells, liver or brain, and from artificial lipid multilayers, this Ca mobilization being apparently unrelated to changes in transglutaminase activity. It is proposed that, in the pancreatic B cell, transglutaminase participates in the machinery controlling the access of secretory granules to the exocytotic sites

A research on determination of quality characteristics of chicken burgers produced with transglutaminase supplementation

Directory of Open Access Journals (Sweden)

Harun URAN

2017-10-01

Full Text Available Abstract Transglutaminases are enzymes that catalyze the cross-linking between peptides or proteins. They play an important role in heat stability, gel-formation capability, water-holding capacity, emulsification and nutritional properties of proteins. They are preferred in the use of a variety of meat products due to the binding properties. In this study the effect of transglutaminase on the quality characteristics of chicken burgers were investigated. The enzyme was added at 5 different concentrations (0.2%, 0.4%, 0.6%, 0.8% and 1% and the other treatments applied in burger production were followed. After the product was formed, it was left in the cold for a while and then analyses were carried out. According to the results, the enzyme contribution did not cause changes in the nutritional items (ash, fat, protein of the product groups. However, there was a significant decrease in the cooking loss and a significant increase in the texture values in the groups in which the enzyme amount was increased. Although the texture of the products have been increased, the transglutaminase treatment did not effect sensory parameters of burgers compared to the control samples. Scanning Electron Microscopy (SEM images also supported to the texture values of samples with the increase of cross-linking in microstructure.

Transglutaminase inhibition: possible therapeutic mechanisms to protect cells from death in neurological disorders

Directory of Open Access Journals (Sweden)

Nicola Gaetano Gatta

2017-10-01

Full Text Available Transglutaminases are a family of Ca2+-dependent enzymes which catalyze post-translational modifications of proteins. The main activity of these enzymes is the cross-linking of glutaminyl residues of a protein/peptide substrate to lysyl residues of a protein/peptide co-substrate. In addition to lysyl residues, other second nucleophilic co-substrates may include monoamines or polyamines (to form mono- or bi-substituted/crosslinked adducts or −OH groups (to form ester linkages. In absence of co-substrates, the nucleophile may be water, resulting in the net deamidation of the glutaminyl residue. Transglutaminase activity has been suggested to be involved in molecular mechanisms responsible for both physiological or pathological processes. In particular, transglutaminase activity has been shown to be responsible for human autoimmune diseases, and Celiac Disease is just one of them. Interestingly, neurodegenerative diseases, such as Alzheimer’s Disease, Parkinson’s Disease, supranuclear palsy, Huntington’s Disease and other polyglutamine diseases, are characterized in part by aberrant cerebral transglutaminase activity and by increased cross-linked proteins in affected brains. Here we describe the possible molecular mechanisms by which these enzymes could be responsible for such diseases and the possible use of transglutaminase inhibitors for patients with diseases characterized by aberrant transglutaminase activity.

Approaches to the production and use of microbial transglutaminase in emulsified meat and vegetable systems

Directory of Open Access Journals (Sweden)

I. A. Glotova

2017-01-01

Full Text Available In the technology of traditional and new forms of food, the modification of structure of proteins is carry out in two opposite directions: the hydrolytic destruction of high-molecular polymers and the artificial creation of polymeric structures of high molecular mass. The transglutaminase preparations (protein-glutamine (-glutamyltransferase, EC 2.3.2.13, TG are used in practical work for realization of the second direction. The main mechanisms of action are polymerization reactions, which lead to a change in the hydrophobicity of protein molecules. The main catalyzed reactions are acyl transfer, binding between glutamine and lysine residues of proteins and deamination. The authors analyzed the approaches to the preparation, properties and studied the joint effect of temperature and pH on the activity of the commercial preparation Revada TG 11 with the application of an enzymatic colorimetric test. The authors studied combined stuffing systems based on beef, pork, poultry mechanical deboning, as well as replacing part of the raw material with protein-carbohydrate compositions with Revada TG 11. The results were used to develop simulated meat systems of biopolymer compositions (SMSBC, approximate in structure and properties to the gels formed by actin and myosin during extraction from myofibrils under the traditional technological processes of meat products production - maturation, salt curing, fine meat grinding. SMSBC includes lupine flour bio-activated by germination, a preparations of dietary fiber as well as a preparation of transglutaminase Revada TG 11. The protein components of the secondary raw materials during the processing of milk such as sodium caseinate, and also whey were used to balance the amino acid composition of the food systems. For practical use, the following options for SMSBC introducing into the composition of minced meat emulsions were recommended by the authors: in the form of hydrated biopolymer dispersion at cutting

Possible Role of the Transglutaminases in the Pathogenesis of Alzheimer's Disease and Other Neurodegenerative Diseases

OpenAIRE

Martin, Antonio; De Vivo, Giulia; Gentile, Vittorio

2011-01-01

Transglutaminases are ubiquitous enzymes which catalyze posttranslational modifications of proteins. Recently, transglutaminase-catalyzed post-translational modification of proteins has been shown to be involved in the molecular mechanisms responsible for human diseases. Transglutaminase activity has been hypothesized to be involved also in the pathogenetic mechanisms responsible for several human neurodegenerative diseases. Alzheimer's disease and other neurodegenerative diseases, such as Pa...

Transglutaminase-Catalyzed Bioconjugation Using One-Pot Metal-Free Bioorthogonal Chemistry.

Science.gov (United States)

Rachel, Natalie M; Toulouse, Jacynthe L; Pelletier, Joelle N

2017-10-18

General approaches for controlled protein modification are increasingly sought-after in the arena of chemical biology. Here, using bioorthogonal reactions, we present combinatorial chemoenzymatic strategies to effectuate protein labeling. A total of three metal-free conjugations were simultaneously or sequentially incorporated in a one-pot format with microbial transglutaminase (MTG) to effectuate protein labeling. MTG offers the particularity of conjugating residues within a protein sequence rather than at its extremities, providing a route to labeling the native protein. The reactions are rapid and circumvent the incompatibility posed by metal catalysts. We identify the tetrazine ligation as most-reactive for this purpose, as demonstrated by the fluorescent labeling of two proteins. The Staudinger ligation and strain-promoted azide-alkyne cycloaddition are alternatives. Owing to the breadth of labels that MTG can use as a substrate, our results demonstrate the versatility of this system, with the researcher being able to combine specific protein substrates with a variety of labels.

Some lessons from the tissue transglutaminase knockout mouse.

Science.gov (United States)

Sarang, Z; Tóth, B; Balajthy, Z; Köröskényi, K; Garabuczi, E; Fésüs, L; Szondy, Z

2009-04-01

Transglutaminase 2 (TG2) is an inducible transamidating acyltransferase that catalyzes Ca(2+)-dependent protein modifications. It acts as a G protein in transmembrane signaling and as a cell surface adhesion mediator, this distinguishes it from other members of the transglutaminase family. The sequence motifs and domains revealed in the TG2 structure, can each be assigned distinct cellular functions, including the regulation of cytoskeleton, cell adhesion, and cell death. Though many biological functions of the enzyme have already been described or proposed previously, studies of TG2 null mice by our laboratory during the past years revealed several novel in vivo roles of the protein. In this review we will discuss these novel roles in their biological context.

Evaluation of the use of transglutaminase in dairy drinks made from goat milk

Directory of Open Access Journals (Sweden)

Daniela Cristina Faria Vieira

2015-02-01

Full Text Available The aim of this study was to evaluate the use of transglutaminase in dairy drinks made from with goat milk with 45% of serum, and the physical, chemical, microbiological and sensory characteristics of these drinks within the expiration date of the product. In the first phase, five different levels of transglutaminase (0, 0.2, 0.3, 0.4, 0.5 U/g were evaluated. In the second phase, the drink that had the best sensory acceptability was evaluated for 30 days. It was observed that the dairy drink treated with 0.5 U/g transglutaminase showed higher sensory acceptability in relation to the 7.18 overall impression. The color values of the dairy drink treated with 0.5 U/g showed no significant difference (p<0.05. The values of lactic acid bacteria are established according to the legislation. Results show the feasibility of the use of transglutaminase in dairy drinks.

Role of Transglutaminase 2 in vascular remodeling

NARCIS (Netherlands)

van den Akker, H.H.O.

2011-01-01

Verschillende vasculaire ziektebeelden, waaronder hoge bloeddruk en verminderde doorbloeding, leiden tot vernauwing van slagadertjes. Het enzym Transglutaminase 2 (TG2) speelt hierbij een belangrijke rol. Jeroen van den Akker onderzocht het achterliggende proces en ontdekte een nieuwe activatieroute

Konjac flour improved textural and water retention properties of transglutaminase-mediated, heat-induced porcine myofibrillar protein gel: Effect of salt level and transglutaminase incubation.

Science.gov (United States)

Chin, Koo B; Go, Mi Y; Xiong, Youling L

2009-03-01

Functional properties of heat-induced gels prepared from microbial transglutaminase (TG)-treated porcine myofibrillar protein (MP) containing sodium caseinate with or without konjac flour (KF) under various salt concentrations (0.1, 0.3 and 0.6MNaCl) were evaluated. The mixed MP gels with KF exhibited improved cooking yields at all salt concentrations. TG treatment greatly enhanced gel strength and elasticity (storage modulus, G') at 0.6M NaCl, but not at lower salt concentrations. The combination of KF and TG improved the gel strength at 0.1 and 0.3M NaCl and G' at all salt concentrations, when compared with non-TG controls. Incubation of MP suspensions (sols) with TG promoted the disappearance of myosin heavy chain and the production of polymers. The TG-treated MP mixed gels had a compact structure, compared to those without TG, and the KF incorporation modified the gel matrix and increased its water-holding capacity. Results from differential scanning calorimetry suggested possible interactions of MP with KF, which may explain the changes in the microstructure of the heat-induced gels.

Viscosity changes of probiotic yoghurt with transglutaminase during storage

Directory of Open Access Journals (Sweden)

Iličić Mirela D.

2008-01-01

Full Text Available The aim of this study was to determine the effect of the quantity of transglutaminase as well as conditions of its application (direct, or after activation by milk heating for 2 h at 40°C and for 1 min at 80°C, on yoghurt viscosity manufactured from two kinds of low fat milk (0.1 % w/w fat and 0.5% w/w fat during 10 days of storage. The fermentation in both series started after the adequate amounts of probiotic starter culture ABT-4 (Chr. Hansen A/S Denmark were added to the milk at 43°C. After milk fermentation at pH 4.5, probiotic yoghurt samples were cooled to 8°C, gently homogenized and packed in plastic containers and stored for 10 days, at +4oC. Viscosity of all samples was measured at 5°C on a Haake Rheostress 600 viscosimeter. On the basis of the obtained results it can be concluded that yoghurt samples produced with low level of transglutaminase activated prior to fermentation have significantly better rheological properties than the samples produced without activation and yoghurt control. Generally, the application of low level transglutaminase in low - fat yoghurt production improves overall rheological properties of the final product.

Microbially-reduced graphene scaffolds to facilitate extracellular electron transfer in microbial fuel cells.

Science.gov (United States)

Yuan, Yong; Zhou, Shungui; Zhao, Bo; Zhuang, Li; Wang, Yueqiang

2012-07-01

A one-pot method is exploited by adding graphene oxide (GO) and acetate into an microbial fuel cell (MFC) in which GO is microbially reduced, leading to in situ construction of a bacteria/graphene network in the anode. The obtained microbially reduced graphene (MRG) exhibits comparable conductivity and physical characteristics to the chemically reduced graphene. Electrochemical measurements reveal that the number of exoelectrogens involved in extracellular electron transfer (EET) to the solid electrode, increases due to the presence of graphene scaffolds, and the EET is facilitated in terms of electron transfer kinetics. As a result, the maximum power density of the MFC is enhanced by 32% (from 1440 to 1905 mW m(-2)) and the coulombic efficiency is improved by 80% (from 30 to 54%). The results demonstrate that the construction of the bacteria/graphene network is an effective alternative to improve the MFC performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

Lactoferrin binding to transglutaminase cross-linked casein micelles

NARCIS (Netherlands)

Anema, S.G.; de Kruif, C.G.|info:eu-repo/dai/nl/073609609

2012-01-01

Casein micelles in skim milk were either untreated (untreated milk) or were cross-linked using transglutaminase (TGA-milk). Added lactoferrin (LF) bound to the casein micelles and followed Langmuir adsorption isotherms. The adsorption level was the same in both milks and decreased the micellar zeta

Physicochemical properties of low sodium frankfurter with added walnut: effect of transglutaminase combined with caseinate, KCl and dietary fibre as salt replacers.

Science.gov (United States)

Colmenero, F Jiménez; Ayo, M J; Carballo, J

2005-04-01

This study compares the effects of combinations of microbial transglutaminase (TGase) and various non-meat ingredients (caseinate, KCl and wheat fibre) used as salt replacers, with the effects of NaCl on the physicochemical properties (cooking loss, emulsion stability, texture and colour) of frankfurters with added walnuts. The combination of TGase with caseinate, KCl or fibre led to harder, springier and chewier (Pcaseinate>KCl>fibre. Frankfurters with caseinate presented the highest lightness and the lowest redness values. Frankfurter with NaCl had a harder, springier and chewier gel/emulsion network with lower cooking loss than those NaCl free.

An overview of electron acceptors in microbial fuel cells

DEFF Research Database (Denmark)

Ucar, Deniz; Zhang, Yifeng; Angelidaki, Irini

2017-01-01

Microbial fuel cells (MFC) have recently received increasing attention due to their promising potential in sustainable wastewater treatment and contaminant removal. In general, contaminants can be removed either as an electron donor via microbial catalyzed oxidization at the anode or removed at t...... acceptors (e.g., nitrate, iron, copper, perchlorate) and mediators....

Exocellular electron transfer in anaerobic microbial communities

NARCIS (Netherlands)

Stams, A.J.M.; Bok, de F.A.M.; Plugge, C.M.; Eekert, van M.H.A.; Dolfing, J.; Schraa, G.

2006-01-01

Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory

Inability of keratinocytes lacking their specific transglutaminase to form cross-linked envelopes: Absence of envelopes as a simple diagnostic test for lamellar ichthyosis

OpenAIRE

Jeon, Saewha; Djian, Philippe; Green, Howard

1998-01-01

Epidermal keratinocytes, late in their terminal differentiation, form cross-linked envelopes resistant to ionic detergent and reducing agent. Because the cross-linking process is catalyzed by the keratinocyte transglutaminase, the absence of active transglutaminase should result in failure of the keratinocyte to form a cross-linked envelope. Three keratinocyte strains bearing mutations in the keratinocyte transglutaminase were examined: two contained no detectable transglutaminase mRNA and no...

Transglutaminase activity in equine strongyles and its potential role in growth and development.

Science.gov (United States)

Rao, U R; Chapman, M R; Singh, R N; Mehta, K; Klei, T R

1999-06-01

Transglutaminases (E.C. 2.3.3.13) are a family of Ca(2+)-dependent enzymes that stabilize protein structure by catalyzing the formation of isopeptide bonds. A novel form of transglutaminase has been identified and characterized that seem to play an important role in growth, development, and molting in adult and larval stages of filarial nematodes. The aim of this study was to identify the ubiquitous nature of this enzyme in other nematodes and to measure its significance to larval growth, molting, and development. For this purpose, equine Strongylus spp. were used. Activity of this enzyme was identified in extracts of larvae and adults of Strongylus vulgaris, S. edentatus, Parascaris equorum and Cylicocyclus insigne. The significance of transglutaminase in the early growth and development of Strongylus vulgaris, S. edentatus and S. equinus was tested by adding specific inhibitors, monodansylcadaverine (MDC) or cystamine (CS), to in vitro cultures of third (L3) and fourth stage larvae (L4). The viability, molting and growth of these nematode species were affected by both inhibitors. Cystamine promoted abnormal development of Strongylus edentatus L3, resulting in an aberrant expansion of the anterior end. Addition of these inhibitors to cultures of L4 also reduced growth of the three species. The results indicated that transglutaminase is present in a wide array of nematode parasites and may be important in growth and development of their larval stages.

Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat

Directory of Open Access Journals (Sweden)

Jerome eBabauta

2014-01-01

Full Text Available Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode with tip size ~20 µm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.

Localized electron transfer rates and microelectrode-based enrichment of microbial communities within a phototrophic microbial mat.

Science.gov (United States)

Babauta, Jerome T; Atci, Erhan; Ha, Phuc T; Lindemann, Stephen R; Ewing, Timothy; Call, Douglas R; Fredrickson, James K; Beyenal, Haluk

2014-01-01

Phototrophic microbial mats frequently exhibit sharp, light-dependent redox gradients that regulate microbial respiration on specific electron acceptors as a function of depth. In this work, a benthic phototrophic microbial mat from Hot Lake, a hypersaline, epsomitic lake located near Oroville in north-central Washington, was used to develop a microscale electrochemical method to study local electron transfer processes within the mat. To characterize the physicochemical variables influencing electron transfer, we initially quantified redox potential, pH, and dissolved oxygen gradients by depth in the mat under photic and aphotic conditions. We further demonstrated that power output of a mat fuel cell was light-dependent. To study local electron transfer processes, we deployed a microscale electrode (microelectrode) with tip size ~20 μm. To enrich a subset of microorganisms capable of interacting with the microelectrode, we anodically polarized the microelectrode at depth in the mat. Subsequently, to characterize the microelectrode-associated community and compare it to the neighboring mat community, we performed amplicon sequencing of the V1-V3 region of the 16S gene. Differences in Bray-Curtis beta diversity, illustrated by large changes in relative abundance at the phylum level, suggested successful enrichment of specific mat community members on the microelectrode surface. The microelectrode-associated community exhibited substantially reduced alpha diversity and elevated relative abundances of Prosthecochloris, Loktanella, Catellibacterium, other unclassified members of Rhodobacteraceae, Thiomicrospira, and Limnobacter, compared with the community at an equivalent depth in the mat. Our results suggest that local electron transfer to an anodically polarized microelectrode selected for a specific microbial population, with substantially more abundance and diversity of sulfur-oxidizing phylotypes compared with the neighboring mat community.

Possible pathophysiological roles of transglutaminase-catalyzed reactions in the pathogenesis of human neurodegenerative diseases

Directory of Open Access Journals (Sweden)

Enrica Serretiello

2015-09-01

Full Text Available Transglutaminases (TG, E.C. 2.3.2.13 are related and ubiquitous enzymes that catalyze the cross linking of a glutaminyl residue of a protein/peptide substrate to a lysyl residue of a protein/peptide co-substrate. These enzymes are also capable of catalyzing other post-translational reactions important for cell life. The distribution and the physiological roles of human TGs have been widely studied in numerous cell types and tissues and recently their roles in several diseases have begun to be identified. It has been hypothesized that transglutaminase activity is directly involved in the pathogenetic mechanisms responsible for several human diseases. In particular, tissue TG (tTG, TG2, a member of the TG enzyme family, has been recently shown to be involved in the molecular mechanisms responsible for a very widespread human pathology, Celiac Disease (CD, one of the most common food intolerances described in the western population. The main food agent that provokes the strong and diffuse clinical symptoms has been known for several years to be gliadin, a protein present in a very large number of human foods derived from vegetables. Recently, some biochemical and immunological aspects of this very common disease have been clarified, and “tissue” transglutaminase, a multifunctional and ubiquitous enzyme, has been identified as one of the major factors. The aim of this review is to summarize the most recent findings concerning the relationships between the biochemical properties of the transglutaminase activity and the basic molecular mechanisms responsible for some human diseases, with particular reference to neuropsychiatric disorders. Possible molecular links between CD and neuropsychiatric disorders, and the use of transglutaminase inhibitors are also discussed.

Quantifying electron fluxes in methanogenic microbial communities

NARCIS (Netherlands)

Junicke, H.

2015-01-01

Anaerobic digestion is a widely applied process in which close interactions between different microbial groups result in the formation of renewable energy in the form of biogas. Nevertheless, the regulatory mechanisms of the electron transfer between acetogenic bacteria and methanogenic archaea in

Transglutaminase involvement in UV-A damage to the eye lens

International Nuclear Information System (INIS)

Weinreb, Orly; Dovrat, A.

1996-01-01

Solar radiation is believed to be one of the major environmental factors involved in lens cataractogenesis. The purpose of the study was to investigate the mechanisms by which UV-A at 365 nm causes damage to the eye lens. Bovine lenses were placed in special culture cells for pre-incubation of 24 hr. The lenses were positioned so that the anterior surface faced the incident UV-A radiation source and were maintained in the cells during irradiation. After irradiation, lens optical quality was monitored throughout the culture period and lens epithelium, cortex and nuclear samples were taken for biochemical analysis. Transglutaminase activity in the lens was affected by the radiation. The activity of transglutaminase in lens epithelium cortex and nucleus increased as a result of the irradiation and then declined towards control levels during the culture period, as the lens recovered from the UV-A damage. Specific lens proteins αB and βB1 crystallins (the enzyme substrates) were analyzed by SDS polyacrylamid gel electrophoreses and immunoblotting with specific antibodies. Seventy-two hours after irradiation of 44.8 J cm -2 UV-A, αB crystallins were affected as was shown by the appearance of aggregation and degradation products. Some protein changes seem to be reversible. It appears that transglutaminase may be involved in the mechanism by which UV-A causes damage to the eye lens. (Author)

Secretory leukocyte protease inhibitor (SLPI is, like its homologue trappin-2 (pre-elafin, a transglutaminase substrate.

Directory of Open Access Journals (Sweden)

Kévin Baranger

Full Text Available Human lungs contain secretory leukocyte protease inhibitor (SLPI, elafin and its biologically active precursor trappin-2 (pre-elafin. These important low-molecular weight inhibitors are involved in controlling the potentially deleterious proteolytic activities of neutrophil serine proteases including elastase, proteinase 3 and cathepsin G. We have shown previously that trappin-2, and to a lesser extent, elafin can be linked covalently to various extracellular matrix proteins by tissue transglutaminases and remain potent protease inhibitors. SLPI is composed of two distinct domains, each of which is about 40% identical to elafin, but it lacks consensus transglutaminase sequence(s, unlike trappin-2 and elafin. We investigated the actions of type 2 tissue transglutaminase and plasma transglutaminase activated factor XIII on SLPI. It was readily covalently bound to fibronectin or elastin by both transglutaminases but did not compete with trappin-2 cross-linking. Cross-linked SLPI still inhibited its target proteases, elastase and cathepsin G. We have also identified the transglutamination sites within SLPI, elafin and trappin-2 by mass spectrometry analysis of tryptic digests of inhibitors cross-linked to mono-dansyl cadaverin or to a fibronectin-derived glutamine-rich peptide. Most of the reactive lysine and glutamine residues in SLPI are located in its first N-terminal elafin-like domain, while in trappin-2, they are located in both the N-terminal cementoin domain and the elafin moiety. We have also demonstrated that the transglutamination substrate status of the cementoin domain of trappin-2 can be transferred from one protein to another, suggesting that it may provide transglutaminase-dependent attachment properties for engineered proteins. We have thus added to the corpus of knowledge on the biology of these potential therapeutic inhibitors of airway proteases.

Production of Transglutaminase by Streptoverticillium ladakanum NRRL-3191 Grown on Media Made from Hydrolysates of Sorghum Straw

Directory of Open Access Journals (Sweden)

Simón J. Téllez-Luis

2004-01-01

Full Text Available The aim of this work was to elucidate the suitability of the biotechnological production of transglutaminase by Streptoverticillium ladakanum NRRL-3191 grown on media made from hydrolysates of sorghum straw. Transglutaminase activity was determined in fermentations on sorghum straw hydrolysates and commercial xylose with initial xylose 10, 20 or 30 g/L. Using media containing commercial xylose 20 g/L, transglutaminase activity up to 0.282 U/mL was obtained in 96 h. Using neutralized, charcoal-treated hydrolysates of sorghum straw with xylose 30 g/L sterilized in autoclave at 121 °C, up to 0.155 U/mL was obtained in 96 h. However, when the sterilization was performed by filtration, using the same hydrolysates with xylose 20 g/L, up to 0.348 U/mL was obtained in 72 h. It was demonstrated that hydrolysates of sorghum straw are suitable media for transglutaminase production by Streptoverticillium ladakanum.

Electron microscopy study of microbial mat in the North Fiji basin hydrothermal vent

Science.gov (United States)

Park, H.; Kim, J. W.; Lee, J. W.

2017-12-01

Hydrothermal vent systems consisting of hydrothermal vent, hydrothermal sediment and microbial mat are widely spread around the ocean, particularly spreading axis, continental margin and back-arc basin. Scientists have perceived that the hydrothermal systems, which reflect the primeval earth environment, are one of the best places to reveal the origin of life and extensive biogeochemical process of microbe-mineral interaction. In the present study multiline of analytical methods (X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM)) were utilized to investigate the mineralogy/chemistry of microbe-mineral interaction in hydrothermal microbial mat. Microbial mat samples were recovered by Canadian scientific submersible ROPOS on South Pacific North Fiji basin KIOST hydrothermal vent expedition 1602. XRD analysis showed that red-colored microbial mat contains Fe-oxides and Fe-oxyhydroxides. Various morphologies of minerals in the red-colored microbial mat observed by SEM are mainly showed sheath shaped, resembled with Leptothrix microbial structure, stalks shaped, similar with Marioprofundus microbial structure and globule shaped microbial structures. They are also detected with DNA analysis. The cross sectional observation of microbial structures encrusted with Fe-oxide and Fe-oxyhydroxide at a nano scale by Transmission Electron Microscopy (TEM) and Focused Ion Beam (FIB) technique was developed to verify the structural/biogeochemical properties in the microbe-mineral interaction. Systematic nano-scale measurements on the biomineralization in the microbial mat leads the understandings of biogeochemical environments around the hydrothermal vent.

Purification of a large molecular weight transglutaminase substrate from liver plasma membranes

International Nuclear Information System (INIS)

Slife, C.W.; Morris, G.S.; Tyrrell, D.J.

1986-01-01

Transglutaminases are enzymes which catalyze the covalent crosslinking of proteins by forming epsilon(γ-glutamyl)lysine isopeptide linkages. In earlier studies, the authors reported that a large molecular weight protein aggregate in rat liver plasma membranes served as a substrate for a plasma membrane-associated transglutaminase. The enzyme specifically incorporated a lysine analog, [ 3 H]putrescine, into a protein complex which remained at the top of an acrylamide gel upon electrophoresis in SDS and reducing agents. The complex has now been isolated by extracting the plasma membranes with detergent (octylglucoside) resuspending the detergent insoluble residues in 6 M guanidine HCl and chromatographing the residue on a 4% agarose column in 6 M guanidine HCl. Most of the radioactivity is found in the void volume fractions from the column. SDS polyacrylamide gel electrophoresis shows that these fractions contain mostly proteins that do not enter the acrylamide gel. Since this purification procedure is essentially the same as that used to isolate a rat hepatocyte adhesion factor from rat liver plasma membranes it is possible that the large molecular weight transglutaminase substrate and the adhesion factor are contained in the same protein aggregate

Modelling the effects of transglutaminase and L-ascorbic acid on substandard quality wheat flour by response surface methodology

Directory of Open Access Journals (Sweden)

Šimurina Olivera D.

2014-01-01

Full Text Available In recent decade, there have been observed extreme variations in climatic conditions which in combination with inadequate agro techniques lead to decreased quality of mercantile wheat, actally flour. The application of improvers can optimise the quality of substandard wheat flour. This paper focuses to systematic analysis of individual and interaction effects of ascorbic acid and transglutaminase as dough strengthening improvers. The effects were investigated using the Response Surface Methodology. Transglutaminase had much higher linear effect on the rheological and fermentative properties of dough from substandard flour than L-ascorbic acid. Both transglutaminase and L-ascorbic acid additions had a significant linear effect on the increase of bread specific volume. Effects of transglutaminase and ascorbic acid are dependent on the applied concentrations and it is necessary to determine the optimal concentration in order to achieve the maximum quality of the dough and bread. Optimal levels of tested improvers were determined using appropriate statistical techniques which applied the desirability function. It was found that the combination of 30 mg/kg of transglutaminase and 75.8 mg/kg of L-ascorbic acid achieved positive synergistic effect on rheological and fermentative wheat dough properties, as well on textural properties and specific volume of bread made from substandard quality flour.

Transglutaminase catalyzed cross-linking of sodium caseinate improves oxidative stability of flaxseed oil emulsion.

Science.gov (United States)

Ma, Hairan; Forssell, Pirkko; Kylli, Petri; Lampi, Anna-Maija; Buchert, Johanna; Boer, Harry; Partanen, Riitta

2012-06-20

Sodium caseinate was modified by transglutaminase catalyzed cross-linking reaction prior to the emulsification process in order to study the effect of cross-linking on the oxidative stability of protein stabilized emulsions. The extent of the cross-linking catalyzed by different dosages of transglutaminase was investigated by following the ammonia production during the reaction and using SDS-PAGE gel. O/W emulsions prepared with the cross-linked and non-cross-linked sodium caseinates were stored for 30 days under the same conditions. Peroxide value measurement, oxygen consumption measurement, and headspace gas chromatography analysis were used to study the oxidative stability of the emulsions. The emulsion made of the cross-linked sodium caseinate showed an improved oxidative stability with reduced formation of fatty acid hydroperoxides and volatiles and a longer period of low rate oxygen consumption. The improving effect of transglutaminase catalyzed cross-linking could be most likely attributed to the enhanced physical stability of the interfacial protein layer against competitive adsorption by oil oxidation products.

Increase of a Calcium Independent Transglutaminase Activity in the Erythrocyte during the Infection with Plasmodium falciparum

Directory of Open Access Journals (Sweden)

Wasserman Moisés

1999-01-01

Full Text Available We have studied the activity of a calcium dependent transglutaminase (EC 2.3.2.13 during the growth of the parasite Plasmodium falciparum inside the infected human erythrocyte. There is only one detectable transglutaminase in the two-cell-system, and its origin is erythrocytic. No activity was detected in preparations of the parasite devoid of erythrocyte cytoplasm. The Michaelis Menten constants (Km of the enzyme for the substrates N'N'dimethylcaseine and putrescine were undistinguishable whether the cell extracts used in their determination were obtained from normal or from infected red cells. The total activity of transglutaminase in stringently synchronized cultures, measured at 0.5mM Ca2+, decreased with the maturation of the parasite. However, a fraction which became irreversibly activated and independent of calcium concentration was detected. The proportion of this fraction grew with maturation; it represented only 20% of the activity in 20 hr-old-trophozoites while in 48-hr-schizonts it was more than 85% of the total activity. The activation of this fraction of transglutaminase did not depend on an increase in the erythrocyte cytoplasmic calcium, since most of the calcium was shown to be located in the parasite.

Improvement of viability of probiotic bacteria, organoleptic qualities and physical characteristics in kefir using transglutaminase and xanthan.

Science.gov (United States)

Sabooni, Pooria; Pourahmad, Rezvan; Adeli, Hamid Reza Mahdavi

2018-01-01

Using kefir as a probiotic food carrier has many benefits. At the same time, it is considered an appropriate product for the dairy industry. The aim of this study was to evaluate the effect of xanthan gum and transglutaminase enzyme on the viability of probiotics and the organoleptic qualities and physicochemical characteristics of kefir. Three levels of transglutaminase enzyme (50, 100 and 150 ppm), and xanthan gum (0.05%, 0.1% and 0.2%) were used. Sensory and physicochemical properties and viability of probiotic bac- teria were measured over 2 weeks of storage at 4°C. By increasing the amounts of xanthan gum and transglutaminase, the viscosity of the samples was increased and syneresis was reduced significantly (P < 0.05). The kefir sample containing 150 ppm enzyme and 0.2% gum had the highest number of probiotic bacteria. Moreover, the highest organoleptic scores were found for this sample. It can be concluded that adding 150 ppm transglutaminase and 0.2% xanthan improved the vi- ability of probiotics and the physical and organoleptic characteristics of kefir.

Microbial electron transport and energy conservation – the foundation for optimizing bioelectrochemical systems

Science.gov (United States)

Kracke, Frauke; Vassilev, Igor; Krömer, Jens O.

2015-01-01

Microbial electrochemical techniques describe a variety of emerging technologies that use electrode–bacteria interactions for biotechnology applications including the production of electricity, waste and wastewater treatment, bioremediation and the production of valuable products. Central in each application is the ability of the microbial catalyst to interact with external electron acceptors and/or donors and its metabolic properties that enable the combination of electron transport and carbon metabolism. And here also lies the key challenge. A wide range of microbes has been discovered to be able to exchange electrons with solid surfaces or mediators but only a few have been studied in depth. Especially electron transfer mechanisms from cathodes towards the microbial organism are poorly understood but are essential for many applications such as microbial electrosynthesis. We analyze the different electron transport chains that nature offers for organisms such as metal respiring bacteria and acetogens, but also standard biotechnological organisms currently used in bio-production. Special focus lies on the essential connection of redox and energy metabolism, which is often ignored when studying bioelectrochemical systems. The possibility of extracellular electron exchange at different points in each organism is discussed regarding required redox potentials and effect on cellular redox and energy levels. Key compounds such as electron carriers (e.g., cytochromes, ferredoxin, quinones, flavins) are identified and analyzed regarding their possible role in electrode–microbe interactions. This work summarizes our current knowledge on electron transport processes and uses a theoretical approach to predict the impact of different modes of transfer on the energy metabolism. As such it adds an important piece of fundamental understanding of microbial electron transport possibilities to the research community and will help to optimize and advance bioelectrochemical

Senescence and programmed cell death in plants: polyamine action mediated by transglutaminase

Directory of Open Access Journals (Sweden)

Stefano eDel Duca

2014-04-01

Full Text Available Research on polyamines in plants laps a long way of about 50 years and many roles have been discovered for these aliphatic cations. Polyamines regulate cell division, differentiation, organogenesis, reproduction, dormancy-break and senescence, homeostatic adjustments in response to external stimuli and stresses. Nevertheless, the molecular mechanisms of their multiple activities are still matter of research. Polyamines are present in free and bound forms and interact with several important cell molecules; some of these interactions may occur by covalent linkages catalyzed by transglutaminase, giving rise to ‘cationisation’ or cross-links among specific proteins. Senescence and PCD can be delayed by polyamines; in order to re-interpret some of these effects and to obtain new insights into their molecular mechanisms, their conjugation has been revised here. The transglutaminase-mediated interactions between proteins and polyamines are the main target of this review. After an introduction on the characteristics of this enzyme, on its catalysis and role in PCD in animals, the plant senescence and PCD models in which TGase has been studied, are presented: the corolla of naturally senescing or excised flowers, the leaves senescing, either excised or not, the pollen during self-incompatible pollination, the hypersensitive response and the tuber storage parenchyma during dormancy release. In all the models examined, transglutaminase appears to be involved by a similar molecular mechanism as described during apoptosis in animal cells, even though several substrates are different. Its effect is probably related to the type of PCD, but mostly to the substrate to be modified in order to achieve the specific PCD program. As a cross-linker of polyamines and proteins, transglutaminase is an important factor involved in multiple, sometimes controversial, roles of polyamines during senescence and PCD.

Microbial growth and sensory quality of dried potato slices irradiated by electrons

International Nuclear Information System (INIS)

Kim, Hyun-Jin; Song, Hyeon-Jeong; Song, Kyung-Bin

2011-01-01

Electron beam irradiation was applied to secure the microbial safety of dried purple sweet potato. After purple sweet potato slices had been dehydrated with 20% (w/w) maltodextrin solution, the samples were irradiated at doses 2, 4, 6, 8, and 10 kGy and then stored at 20 o C for 60 days. Microbiological data indicated that the populations of total aerobic bacteria and of yeast and molds significantly decreased with increase in irradiation dosage. Specifically, microbial load was reduced by about three log cycles at 6 kGy compared to those of the control. Based on the color measurement of the potato slices, electron beam irradiation treatment did not affect the color quality. Sensory evaluation results also showed that electron beam irradiation did not affect overall sensory scores during storage. These results suggest that electron beam irradiation could be useful for improving microbial safety without impairing the quality of the potato slices during storage.

Electron-beam and microwave treatment of some microbial strains

International Nuclear Information System (INIS)

Martin, D.; Ferdes, O.S.; Minea, R.; Tirlea, A.; Badea, M.; Plamadeala, S.; Ferdes, M.

1998-01-01

The experimental results concerning the combined effects of microwaves and accelerated electron beams on various microbial strains such as E. coli, Salmonella sp. and Monascus purpureus are presented. A special designed microwave applicator with a 2.45 GHz frequency CW magnetron of 850 maximum output power and with associate electronics that allow to control the microwave power, the current intensity, and the exposure time was used. The electron-beam irradiation was performed at different irradiation doses and at a dose rate of 1.5 - 2.0 kGy/min by using a linac at a mean electron energy about 6 MeV, mean bean current of 10 μA, pulse period of 3.5 μs and repetition frequency 100 Hz. The experiments were carried out in 5 variants: microwave treatment; electron-beam irradiation; microwaves followed by electron beam; electrons followed by microwaves; and simultaneous application of microwaves and electron beam. The microbiocidal effect was found to be enhanced by additional use of microwave energy to electron beam irradiation. Enhancement of inactivation rate is only remarkable for the microwave treatment or simultaneous electron beam and microwave irradiation at a temperature above the critical value at which microorganisms begin to perish by heat. Simultaneous irradiation with electron beam and microwaves results in a reduction of temperature and time as well as in the decrease of the upper limit of required electron beam absorbed dose for an assumed microbiological quality parameter. The results obtained indicate the occurrence of a synergistic effect of the two physical fields on a non-thermal basis. Hence, combined microwave-electron beam treatment may be applied as an effective method to reduce microbial load

Transglutaminase-2 differently regulates cartilage destruction and osteophyte formation in a surgical model of osteoarthritis.

Science.gov (United States)

Orlandi, A; Oliva, F; Taurisano, G; Candi, E; Di Lascio, A; Melino, G; Spagnoli, L G; Tarantino, U

2009-04-01

Osteoarthritis is a progressive joint disease characterized by cartilage degradation and bone remodeling. Transglutaminases catalyze a calcium-dependent transamidation reaction that produces covalent cross-linking of available substrate glutamine residues and modifies the extracellular matrix. Increased transglutaminases-mediated activity is reported in osteoarthritis, but the relative contribution of transglutaminases-2 (TG2) is uncertain. We describe TG2 expression in human femoral osteoarthritis and in wild-type and homozygous TG2 knockout mice after surgically-induced knee joint instability. Increased TG2 levels were observed in human and wild-type murine osteoarthritic cartilage compared to the respective controls. Histomorphometrical but not X-ray investigation documented in osteoarthritic TG2 knockout mice reduced cartilage destruction and an increased osteophyte formation compared to wild-type mice. These differences were associated with increased TGFbeta-1 expression. In addition to confirming its important role in osteoarthritis development, our results demonstrated that TG2 expression differently influences cartilage destruction and bone remodeling, suggesting new targeted TG2-related therapeutic strategies.

Tissue specific and androgen-regulated expression of human prostate-specific transglutaminase

NARCIS (Netherlands)

H.J. Dubbink (Erik Jan); N.S. Verkaik (Nicole); P.W. Faber; J. Trapman (Jan); F.H. Schröder (Fritz); J.C. Romijn (Johannes)

1996-01-01

textabstractTransglutaminases (TGases) are calcium-dependent enzymes catalysing the post-translational cross-linking of proteins. In the prostate at least two TGases are present, the ubiquitously expressed tissue-type TGase (TGC), and a prostate-restricted TGase (TGP).

THE EFFECT OF TRANSGLUTAMINASE ON THE RHEOLOGICAL PROPERTIES OF YOGURT

Directory of Open Access Journals (Sweden)

Iuliana Aprodu

2011-05-01

Full Text Available The aim of this study was to investigate the rheological characteristics of yogurts obtained from milk treated with transglutaminase prior to fermentation with Streptococus theromophilus and Lactobacillus delbrueckii subsp. Bulgaricus. A set of 36 experiments were carried out to test the influence of various enzyme concentrations ranging from 0 to 0.04%, different setting temperatures (35, 40 and 45 oC, and setting time (60, 90 and 120 min. The cross-linking of milk proteins influenced the post-acidification process as well as the stability of the yogurt samples. The enzymatic treatment of milk allowed avoiding the syneresis phenomena during yogurt storage at 4 oC; the water holding capacity during centrifugation was also improved. Concerning the rheological properties, the apparent viscosity of yogurt increased by increasing the enzyme concentration and the setting time for the entire tested domain of shear rates. The results indicate that transglutaminase catalyzed cross-linking is an effective tool for improving functional properties of yogurt.

Transglutaminase-catalyzed amination of pea protein peptides using the biogenic amines histamine and tyramine.

Science.gov (United States)

Lu, Xinyao; Hrynets, Yuliya; Betti, Mirko

2017-06-01

Biogenic amines (BAs) are produced by the enzymatic decarboxylation of amino acids, and are well-known for their toxicity to humans. This study describes a new method using microbial transglutaminase (MTGase) to covalently link BAs such as histamine (HIS) and tyramine (TYR) to the glutamine residues of alcalase-hydrolyzed pea protein (PPH). The incubation of PPH and HIS and TYR in the presence of MTGase at 37 °C led to the formation of conjugates, as determined by liquid chromatography, after derivatization with dansyl chloride. Seventy-six % of HIS and 65% of TYR were covalently incorporated to PPH by MTGase. The incubation of PPH and TYR in the presence of MTGase exhibited a 52% DPPH radical scavenging activity at 10 mg mL -1 . Conjugation via MTGase improved the antioxidant status by reducing lipid peroxidation. This study emphasizes that the application of MTGase can effectively reduce histamine and tyramine content while simultaneously enhancing antioxidative capacity of PPH. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Lack of induction of tissue transglutaminase but activation of the preexisting enzyme in c-Myc-induced apoptosis of CHO cells.

Science.gov (United States)

Balajthy, Z; Kedei, N; Nagy, L; Davies, P J; Fésüs, L

1997-07-18

The intracellular activity and expression of tissue transglutaminase, which crosslinks proteins through epsilon(gamma-glutamyl)lysine isodipeptide bond, was investigated in CHO cells and those stably transfected with either inducible c-Myc (which leads to apoptosis) or with c-myc and the apoptosis inhibitor Bcl-2. Protein-bound cross-link content was significantly higher when apoptosis was induced by c-Myc while the concomitant presence of Bcl-2 markedly reduced both apoptosis and enzymatic protein cross-linking. The expression of tissue transglutaminase did not change following the initiation of apoptosis by c-Myc or when it was blocked by Bcl-2. Studying transiently co-transfected elements of the mouse tissue transglutaminase promoter linked to a reporter enzyme revealed their overall repression in cells expressing c-Myc. This repression was partially suspended in cells also carrying Bcl-2. Our data suggest that tissue transglutaminase is not induced when c-Myc initiates apoptosis but the pre-existing endogenous enzyme is activated.

Imaging hydrated microbial extracellular polymers: Comparative analysis by electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Dohnalkova, A.C.; Marshall, M. J.; Arey, B. W.; Williams, K. H.; Buck, E. C.; Fredrickson, J. K.

2011-01-01

Microbe-mineral and -metal interactions represent a major intersection between the biosphere and geosphere but require high-resolution imaging and analytical tools for investigating microscale associations. Electron microscopy has been used extensively for geomicrobial investigations and although used bona fide, the traditional methods of sample preparation do not preserve the native morphology of microbiological components, especially extracellular polymers. Herein, we present a direct comparative analysis of microbial interactions using conventional electron microscopy approaches of imaging at room temperature and a suite of cryogenic electron microscopy methods providing imaging in the close-to-natural hydrated state. In situ, we observed an irreversible transformation of the hydrated bacterial extracellular polymers during the traditional dehydration-based sample preparation that resulted in their collapse into filamentous structures. Dehydration-induced polymer collapse can lead to inaccurate spatial relationships and hence could subsequently affect conclusions regarding nature of interactions between microbial extracellular polymers and their environment.

Set anode potentials affect the electron fluxes and microbial community structure in propionate-fed microbial electrolysis cells

KAUST Repository

Rao, Hari Ananda

2016-12-09

Anode potential has been shown to be a critical factor in the rate of acetate removal in microbial electrolysis cells (MECs), but studies with fermentable substrates and set potentials are lacking. Here, we examined the impact of three different set anode potentials (SAPs; −0.25, 0, and 0.25 V vs. standard hydrogen electrode) on the electrochemical performance, electron flux to various sinks, and anodic microbial community structure in two-chambered MECs fed with propionate. Electrical current (49–71%) and CH4 (22.9–41%) were the largest electron sinks regardless of the potentials tested. Among the three SAPs tested, 0 V showed the highest electron flux to electrical current (71 ± 5%) and the lowest flux to CH4 (22.9 ± 1.2%). In contrast, the SAP of −0.25 V had the lowest electron flux to current (49 ± 6%) and the highest flux to CH4 (41.1 ± 2%). The most dominant genera detected on the anode of all three SAPs based on 16S rRNA gene sequencing were Geobacter, Smithella and Syntrophobacter, but their relative abundance varied among the tested SAPs. Microbial community analysis implies that complete degradation of propionate in all the tested SAPs was facilitated by syntrophic interactions between fermenters and Geobacter at the anode and ferementers and hydrogenotrophic methanogens in suspension.

Size measuring techniques as tool to monitor pea proteins intramolecular crosslinking by transglutaminase treatment.

Science.gov (United States)

Djoullah, Attaf; Krechiche, Ghali; Husson, Florence; Saurel, Rémi

2016-01-01

In this work, techniques for monitoring the intramolecular transglutaminase cross-links of pea proteins, based on protein size determination, were developed. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis profiles of transglutaminase-treated low concentration (0.01% w/w) pea albumin samples, compared to the untreated one (control), showed a higher electrophoretic migration of the major albumin fraction band (26 kDa), reflecting a decrease in protein size. This protein size decrease was confirmed, after DEAE column purification, by dynamic light scattering (DLS) where the hydrodynamic radius of treated samples appears to be reduced compared to the control one. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of the large subunit of Ribulose 1,5-bisphosphate carboxylase/oxygenase as a substrate for transglutaminase in Medicageo sativa L. (alfalfa)

International Nuclear Information System (INIS)

Margosiak, S.A.; Dharma, A.; Carver, M.R.B.; Gonzales, A.P.; Louie, D.; Kuehn, G.D.

1990-01-01

Extract prepared from floral meristematic tissue of alfalfa (Medicago sativa L.) were investigated for expression of the enzyme transglutaminase in order to identify the major protein substrate for transglutaminase-directed modifications among plant proteins. The large polymorphic subunits of ribulose 1,5-bisphosphate carboxylase/oxygenase in alfalfa, with molecular weights of 52,700 and 57,600, are major substrates for transglutaminase in these extracts. This was established by: (a) covalent conjugation of monodansylcadaverine to the large subunit followed by fluorescent detection in SDS-polyacrylamide gels; (b) covalent conjugation of [ 14 C]putrescine to the large subunit with detection by autoradiography; (c) covalent conjugation of monodansylcadaverine to the large subunit and demonstration of immunocross-reactivity on nitrocellulose transblot of the modified large subunit with antibody prepared in rabbits against dansylated-ovalbumin; (d) demonstration of a direct dependence of the rate of transglutaminase-mediated, [ 14 C]putresciene incorporation upon the concentration of ribulose, 1,5-bisphosphate carboxylase/oxygenase from alfalfa or spinach; and (e) presumptive evidence from size exclusion chromatography that transglutaminase may cofractionate with native molecules of ribulose 1,5-bisphosphate carboxylase/oxygenase in crude extracts

Short communication: Effect of whey protein addition and transglutaminase treatment on the physical and sensory properties of reduced-fat ice cream.

Science.gov (United States)

Danesh, Erfan; Goudarzi, Mostafa; Jooyandeh, Hossein

2017-07-01

The effects of whey protein addition and transglutaminase treatment, alone and in combination, on the physical and sensory properties of reduced-fat ice cream were investigated. Adding whey protein with or without enzyme treatment decreased melting rate, overrun, and hardness of the reduced-fat ice cream; however, the enzyme-treated sample had a higher melting rate and overrun and softer texture. Whey protein-fortified samples showed higher melting resistance, but lower overrun and firmer texture compared with the enzyme-treated sample without added whey protein. Whey protein addition with or without transglutaminase treatment caused an increase in apparent viscosity and a decrease in flow index of the reduced-fat ice cream; nevertheless, the flow behavior of full-fat sample was most similar to the enzyme-treated reduced-fat sample with no added whey protein. Descriptive sensory analyses showed that neither whey protein addition nor transglutaminase treatment significantly influenced the flavor and odor of reduced-fat ice cream, but they both noticeably improved the color and texture of the final product. The results of this study suggest that whey protein addition with transglutaminase treatment improves the physical and sensory properties of reduced-fat ice cream more favorably than does whey protein addition or transglutaminase treatment alone. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Quality characteristics of gluten-free cookies made of buckwheat, corn, and rice flour with/without transglutaminase.

Science.gov (United States)

Altındağ, Gülçin; Certel, Muharrem; Erem, Fundagül; İlknur Konak, Ülgen

2015-04-01

Buckwheat is one of the most valuable pseudo-cereals in terms of its nutritional composition, and it is suitable for celiac patients because of its gluten-free characteristic. However, gluten is the main structure-forming protein responsible for the development of structure in baked products. Therefore, it is a challenge to produce high-quality gluten-free products. Transglutaminase addition is a relatively common application used in the production of gluten-free baked goods. The objective of this study was to investigate the combination of buckwheat flour with rice and corn flour at different levels in gluten-free cookie formulations and the impact of transglutaminase on the quality of cookies. Quality parameters evaluated were proximal chemical composition, spread ratio, color, and textural parameters (hardness and fracturability). Spread ratio, protein, crude fiber, ash content, and also b* and hardness values were significantly (p flour combinations. Further, addition of transglutaminase resulted in increased moisture content, spread ratio, and fracturability but decreased hardness values. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Effects of gluten and transglutaminase on microstructure, sensory characteristics and instrumental texture of oat bread

Directory of Open Access Journals (Sweden)

M. SALMENKALLIO-MARTTILA

2008-12-01

Full Text Available Effects of added gluten and transglutaminase on microstructure, instrumental texture and sensory characteristics of bread baked with 51% wholemeal oat flour were compared in order to determine how changes in the state of macromolecules – protein and starch – correlate with changes in sensory and instrumental structure. Light microscopy, instrumental texture profile analysis, and descriptive sensory analysis were used to analyse the test breads. Addition of gluten and transglutaminase affected the structure of the protein network and distribution of water between the protein and starch phases. The differences in microstructure were quantified by determining the areas of starch and protein in the micrographs by image analysis. Breads baked with added gluten and water were softer and less gummy than the oat and wheat reference breads in the texture profile analysis. Addition of transglutaminase made the breads harder and gummier than the breads baked without the added enzyme. In the descriptive sensory analysis breads baked with added gluten or added gluten and water were evaluated as more soft and springy than the reference oat bread. Sensory characteristics of bread texture correlated well with the texture and microstructure measured instrumentally.;

Tissue-transglutaminase contributes to neutrophil granulocyte differentiation and functions.

Science.gov (United States)

Balajthy, Zoltán; Csomós, Krisztián; Vámosi, György; Szántó, Attila; Lanotte, Michel; Fésüs, László

2006-09-15

Promyelocytic NB4 leukemia cells undergo differentiation to granulocytes following retinoic acid treatment. Here we report that tissue transglutaminase (TG2), a protein cross-linking enzyme, was induced, then partially translocated into the nucleus, and became strongly associated with the chromatin during the differentiation process. The transglutaminase-catalyzed cross-link content of both the cytosolic and the nuclear protein fractions increased while NB4 cells underwent cellular maturation. Inhibition of cross-linking activity of TG2 by monodansylcadaverin in these cells led to diminished nitroblue tetrazolium (NBT) positivity, production of less superoxide anion, and decreased expression of GP91PHOX, the membrane-associated subunit of NADPH oxidase. Neutrophils isolated from TG2(-/-) mice showed diminished NBT reduction capacity, reduced superoxide anion formation, and down-regulation of the gp91phox subunit of NADPH oxidase, compared with wild-type cells. It was also observed that TG2(-/-) mice exhibited increased neutrophil phagocytic activity, but had attenuated neutrophil chemotaxis and impaired neutrophil extravasation with higher neutrophil counts in their circulation during yeast extract-induced peritonitis. These results clearly suggest that TG2 may modulate the expression of genes related to neutrophil functions and is involved in several intracellular and extracellular functions of extravasating neutrophil.

Rheological Enhancement of Pork Myofibrillar Protein-Lipid Emulsion Composite Gels via Glucose Oxidase Oxidation/Transglutaminase Cross-Linking Pathway.

Science.gov (United States)

Wang, Xu; Xiong, Youling L; Sato, Hiroaki

2017-09-27

Porcine myofibrillar protein (MP) was modified with glucose oxidase (GluOx)-iron that produces hydroxyl radicals then subjected to microbial transglutaminase (TGase) cross-linking in 0.6 M NaCl at 4 °C. The resulting aggregation and gel formation of MP were examined. The GluOx-mediated oxidation promoted the formation of both soluble and insoluble protein aggregates via disulfide bonds and occlusions of hydrophobic groups. The subsequent TGase treatment converted protein aggregates into highly cross-linked polymers. MP-lipid emulsion composite gels formed with such polymers exhibited markedly enhanced gelling capacity: up to 4.4-fold increases in gel firmness and 3.5-fold increases in gel elasticity over nontreated protein. Microstructural examination showed small oil droplets dispersed in a densely packed gel matrix when MP was oxidatively modified, and the TGase treatment further contributed to such packing. The enzymatic GluOx oxidation/TGase treatment shows promise to improve the textural properties of emulsified meat products.

Isoenergic modification of whey protein structure by denaturation and crosslinking using transglutaminase

DEFF Research Database (Denmark)

Stender, Emil G. P.; Koutina, Glykeria; Almdal, Kristoffer

2018-01-01

Transglutaminase (TG) catalyzes formation of covalent bonds between lysine and glutamine side chains and has applications in manipulation of food structure. Physical properties of a whey protein mixture (SPC) denatured either at elevated pH or by heat-treatment and followed by TG catalyzed...

Structural and Functional Characterization of an Ancient Bacterial Transglutaminase Sheds Light on the Minimal Requirements for Protein Cross-Linking.

Science.gov (United States)

Fernandes, Catarina G; Plácido, Diana; Lousa, Diana; Brito, José A; Isidro, Anabela; Soares, Cláudio M; Pohl, Jan; Carrondo, Maria A; Archer, Margarida; Henriques, Adriano O

2015-09-22

Transglutaminases are best known for their ability to catalyze protein cross-linking reactions that impart chemical and physical resilience to cellular structures. Here, we report the crystal structure and characterization of Tgl, a transglutaminase from the bacterium Bacillus subtilis. Tgl is produced during sporulation and cross-links the surface of the highly resilient spore. Tgl-like proteins are found only in spore-forming bacteria of the Bacillus and Clostridia classes, indicating an ancient origin. Tgl is a single-domain protein, produced in active form, and the smallest transglutaminase characterized to date. We show that Tgl is structurally similar to bacterial cell wall endopeptidases and has an NlpC/P60 catalytic core, thought to represent the ancestral unit of the cysteine protease fold. We show that Tgl functions through a unique partially redundant catalytic dyad formed by Cys116 and Glu187 or Glu115. Strikingly, the catalytic Cys is insulated within a hydrophobic tunnel that traverses the molecule from side to side. The lack of similarity of Tgl to other transglutaminases together with its small size suggests that an NlpC/P60 catalytic core and insulation of the active site during catalysis may be essential requirements for protein cross-linking.

Nε-Acryloyllysine Piperazides as Irreversible Inhibitors of Transglutaminase 2: Synthesis, Structure-Activity Relationships, and Pharmacokinetic Profiling.

Science.gov (United States)

Wodtke, Robert; Hauser, Christoph; Ruiz-Gómez, Gloria; Jäckel, Elisabeth; Bauer, David; Lohse, Martin; Wong, Alan; Pufe, Johanna; Ludwig, Friedrich-Alexander; Fischer, Steffen; Hauser, Sandra; Greif, Dieter; Pisabarro, M Teresa; Pietzsch, Jens; Pietsch, Markus; Löser, Reik

2018-05-24

Transglutaminase 2 (TGase 2)-catalyzed transamidation represents an important post-translational mechanism for protein modification with implications in physiological and pathophysiological conditions, including fibrotic and neoplastic processes. Consequently, this enzyme is considered a promising target for the diagnosis of and therapy for these diseases. In this study, we report on the synthesis and kinetic characterization of N ε -acryloyllysine piperazides as irreversible inhibitors of TGase 2. Systematic structural modifications on 54 new compounds were performed with a major focus on fluorine-bearing substituents due to the potential of such compounds to serve as radiotracer candidates for positron emission tomography. The determined inhibitory activities ranged from 100 to 10 000 M -1 s -1 , which resulted in comprehensive structure-activity relationships. Structure-activity correlations using various substituent parameters accompanied by covalent docking studies provide an advanced understanding of the molecular recognition for this inhibitor class within the active site of TGase 2. Selectivity profiling of selected compounds for other transglutaminases demonstrated an excellent selectivity toward transglutaminase 2. Furthermore, an initial pharmacokinetic profiling of selected inhibitors was performed, including the assessment of potential membrane permeability and liver microsomal stability.

Transglutaminase 2: Friend or foe? The discordant role in neurons and astrocytes.

Science.gov (United States)

Quinn, Breandan R; Yunes-Medina, Laura; Johnson, Gail V W

2018-03-23

Members of the transglutaminase family catalyze the formation of isopeptide bonds between a polypeptide-bound glutamine and a low molecular weight amine (e.g., spermidine) or the ɛ-amino group of a polypeptide-bound lysine. Transglutaminase 2 (TG2), a prominent member of this family, is unique because in addition to being a transamidating enzyme, it exhibits numerous other activities. As a result, TG2 plays a role in many physiological processes, and its function is highly cell type specific and relies upon a number of factors, including conformation, cellular compartment location, and local concentrations of Ca 2+ and guanine nucleotides. TG2 is the most abundant transglutaminase in the central nervous system (CNS) and plays a pivotal role in the CNS injury response. How TG2 affects the cell in response to an insult is strikingly different in astrocytes and neurons. In neurons, TG2 supports survival. Overexpression of TG2 in primary neurons protects against oxygen and glucose deprivation (OGD)-induced cell death and in vivo results in a reduction in infarct volume subsequent to a stroke. Knockdown of TG2 in primary neurons results in a loss of viability. In contrast, deletion of TG2 from astrocytes results in increased survival following OGD and improved ability to protect neurons from injury. Here, a brief overview of TG2 is provided, followed by a discussion of the role of TG2 in transcriptional regulation, cellular dynamics, and cell death. The differing roles TG2 plays in neurons and astrocytes are highlighted and compared to how TG2 functions in other cell types. © 2018 Wiley Periodicals, Inc.

Bar-coded pyrosequencing reveals the responses of PBDE-degrading microbial communities to electron donor amendments.

Directory of Open Access Journals (Sweden)

Meiying Xu

Full Text Available Polybrominated diphenyl ethers (PBDEs can be reductively degraded by microorganisms under anaerobic conditions. However, little is known about the effect of electron donors on microbial communities involved in PBDEs degradation. Here we employed 454 Titanium pyrosequencing to examine the phylogenetic diversity, composition, structure and dynamics of microbial communities from microcosms under the conditions of different electron donor amendments. The community structures in each of the five alternate electron donor enrichments were significantly shifted in comparison with those of the control microcosm. Commonly existing OTUs between the treatment and control consortia increased from 5 to 17 and more than 50% of OTUs increased around 13.7 to 186 times at least in one of the microcosms after 90-days enrichment. Although the microbial communities at different taxonomic levels were significantly changed by different environmental variable groups in redundancy analysis, significant correlations were observed between the microbial communities and PBDE congener profiles. The lesser-brominated PBDE congeners, tri-BDE congener (BDE-32 and hexa-BDE, were identified as the key factors shaping the microbial community structures at OTU level. Some rare populations, including the known dechlorinating bacterium, Dehalobacter, showed significant positive-correlation with the amounts of PBDE congeners in the consortia. The same results were also observed on some unclassified bacteria. These results suggest that PBDEs-degrading microbial communities can be successfully enriched, and their structures and compositions can be manipulated through adjusting the environmental parameters.

Application of transglutaminase and fermizyme for sensory quality improvement of pastry.

Science.gov (United States)

Hozová, Bernadetta; Kukurová, Iveta; Dodok, Ladislav

2003-06-01

The objective of the model experiment was to find out the improving effect of two selected enzymes, transglutaminase (i) and fermizyme (ii), added at different concentrations of 4.5 mg and 7.5 mg/300 g flour (i) and 15 mg and 60 mg/300 g flour (ii) to the pastry dough on the quality of end products. The investigation was aimed to observe some changes of the sensory parameters (sensory profile) of pastry produced from the freezer-stored dough (-18 +/- 2 degrees C/0, 1, 7 and 14 days), namely shape (camber), odour, taste, crust colour (thickness/hardness), crumb elasticity (porosity, colour, hardness), adhesiveness to palate, etc. It has been ascertained that the sensory quality is favourably affected by the addition of the lower concentration of both enzymes: transglutaminase, 4.5 mg/300 g flour and fermizyme, 15 mg/300 g flour in comparison to the control without enzymes. The cambering ratio values and other sensory profile parameters of pastry gradually decreased during the freezer storage of dough. The best sensory evaluation of both kinds of pastry was achieved after a one-day storage of doughs.

Rheology, microstructure and baking characteristics of frozen dough containing Rhizopus chinensis lipase and transglutaminase

Science.gov (United States)

The beneficial effects of a new recombinant lipase (Rhizopus chinensis lipase, RCL) and transglutaminase (TG) were investigated on frozen dough systems and their breadmaking quality. Rheological properties and microstructure of doughs were measured using a dynamic rheometer, rheofermentometer F3, an...

Outward electron transfer by Saccharomyces cerevisiae monitored with a bi-cathodic microbial fuel cell-type activity sensor.

Science.gov (United States)

Ducommun, Raphaël; Favre, Marie-France; Carrard, Delphine; Fischer, Fabian

2010-03-01

A Janus head-like bi-cathodic microbial fuel cell was constructed to monitor the electron transfer from Saccharomyces cerevisiae to a woven carbon anode. The experiments were conducted during an ethanol cultivation of 170 g/l glucose in the presence and absence of yeast-peptone medium. First, using a basic fuel-cell type activity sensor, it was shown that yeast-peptone medium contains electroactive compounds. For this purpose, 1% solutions of soy peptone and yeast extract were subjected to oxidative conditions, using a microbial fuel cell set-up corresponding to a typical galvanic cell, consisting of culture medium in the anodic half-cell and 0.5 M K(3)Fe(CN)(6) in the cathodic half-cell. Second, using a bi-cathodic microbial fuel cell, it was shown that electrons were transferred from yeast cells to the carbon anode. The participation of electroactive compounds in the electron transport was separated as background current. This result was verified by applying medium-free conditions, where only glucose was fed, confirming that electrons are transferred from yeast cells to the woven carbon anode. Knowledge about the electron transfer through the cell membrane is of importance in amperometric online monitoring of yeast fermentations and for electricity production with microbial fuel cells. Copyright (c) 2009 John Wiley & Sons, Ltd.

Transglutaminase (TG) involvement in early embryogenesis

International Nuclear Information System (INIS)

Maccioni, R.B.; Arechaga, J.

1986-01-01

Transglutaminase (TG) has been examined in different stages of preimplantation mouse embryogenesis. The specific activity of this enzyme in the soluble cellular fraction increases 2-fold from 2-cell embryos to 8-cell morulae and 4-fold from 2-cell embryos to blastocyst. The same developmental profile was seen when either N,N-dimethylcasein or endogenous substrates were used in the TG assay. Using high-speed supernatants from different stage embryos as a source of enzyme and [ 3 H]putrescine as acyl acceptor, the major acyl donor components were tubulin and a high molecular weight (HMW) cross-linkage product, as assessed by electrophoresis and immunoblotting. When either assembled or monomeric cytoskeleton proteins were compared as subtrates, microtubules were the best acyl donors. These studies indicate that TG activity is modulated during the changing demands of blastomeres for microtubule cytoskeleton in early embryogenesis

Prevalence of IgA Antibodies to Endomysium and Tissue Transglutaminase in Primary Biliary Cirrhosis

Directory of Open Access Journals (Sweden)

Helen R Gillett

2000-01-01

Full Text Available The association between celiac disease and primary biliary cirrhosis has been described in several case reports and small screening studies, with varying prevalence rates. Stored sera from 378 patients with primary biliary cirrhosis were tested for immunoglobulin (Ig A endomysium and tissue transglutaminase antibodies. Ten patients were positive for both antibodies (2.6%; five of these patients had had small bowel biopsies confirming celiac disease. A further 44 patients (11.6% had raised titres of IgA tissue transglutaminase antibody but were negative for IgA endomysium antibody. The increased prevalence of celiac-related antibodies in patients with primary biliary cirrhosis suggests that the two conditions are associated, although the reason for the association remains unclear. Patients with primary biliary cirrhosis should be considered to be at high risk for celiac disease. Although liver biochemistry does not improve when these patients are fed a gluten-free diet, the complications of untreated celiac disease warrant the identification and treatment of the condition in this population.

Enhancing the rheological performance of wheat flour dough with glucose oxidase, transglutaminase or supplementary gluten

NARCIS (Netherlands)

Meerts, Mathieu; Van Ammel, Helene; Meeus, Yannick; Van Engeland, Sarah; Cardinaels, Ruth; Oosterlinck, Filip; Courtin, Christophe M.; Moldenaers, Paula

2017-01-01

The enzymes glucose oxidase and transglutaminase are frequently used to improve the breadmaking performance of wheat flours, as they have the ability to considerably alter the viscoelastic nature of the gluten network. To evaluate a flour’s breadmaking performance, rheological tests offer an

Influence of transglutaminase treatment on the physicochemical, rheological, and melting properties of ice cream prepared from goat milk

Directory of Open Access Journals (Sweden)

Hatice Şanlidere Aloğlu

2018-01-01

Full Text Available This study was conducted to evaluate the effects of the transglutaminase enzyme on the physicochemical characteristics, overrun, melting resistance, rheological and sensorial properties of ice cream made from goat’s milk. Different enzyme units (0.5, 1, 2, and 4 U/g milk protein and treatment times (20 min and 60 min were applied to determine the optimum process conditions. Treatment of the transglutaminase in the ice cream mix significantly affected the rheological and melting properties of the ice cream samples. The samples prepared with higher enzyme units and enzyme-treatment times showed higher melting resistance, consistency index, and viscoelastic modulus (G’ than the ice cream mix. The correlation coefficient between melting resistance and viscoelastic modulus was found to be high (0.76. The apparent viscosity of all samples decreased with increasing the shear rate, indicating that all samples exhibited non-Newtonian shear thinning flow behavior. The sensory, overrun, and physicochemical properties of samples were not affected by the enzyme treatment. This study showed that treatment times and enzyme units are essential factors in the processing of the transglutaminase enzyme for improving the rheological and melting properties of ice cream mixes. Another significant result was that desired melting resistance could be achieved for ice cream with lower stabilizer and fat content.

UN-EDITED VERSION

Indian Academy of Sciences (India)

71

H197 and characterization of microbial transglutaminase. 2. Wenjie Wan .... TGs are widely found in animals (Folk et al. 1966a; Schmid et al. ... transglutaminase has been made to get new variants with heat-resistance and. 57 heat-sensitive ...

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

The decrease of microbial charge in some spices by electron beam irradiation

International Nuclear Information System (INIS)

Ferdes, Mariana; Ferdes, Ovidiu

2008-01-01

The radiations of primary interest in food preservation are ionizing radiations; the use of electron accelerators offers certain advantages like high efficiency and flexibility in the choice of surface and depth treatments for a variety of food items. The paper presents the influence of ionising radiation on the microbial content in different spices: nutmeg, paprika, savory, ginger and oregano. The electron beam irradiation at doses within the range of 1-10 kGy reduced the values of CFU/g of total counts of aerobic germs and also of yeasts and moulds in these food products. The D 10 and D L for each sample were determined from the inactivation curves. For each food item the D L values for total aerobic microflora are higher than the corresponding D L values for fungi. In conclusion, values doses of 10 kGy are sufficient to reduce the microbial load of these spices under the values permitted by law. (authors)

Effect of Rosemary Transglutaminase on Yoghurt Fortified with Whey Protein Isolate

Directory of Open Access Journals (Sweden)

Ibrahim Osama

2017-12-01

Full Text Available Rosemary (Rosmarinus officinalis L. transglutaminase (RTGase was used to cross-link whey protein isolate (WPI and its ability to induce gelation was investigated. The rheological and textural properties of WPI were improved with RTGase treatment. Set-type yoghurts fortified with 1% WPI powder treated with RTGase at the level of 2.5 and 10 unit/g protein were studied. Chemical, rheological, textural and organoleptic properties of the yoghurt treated with RTGase were better than these of the control yoghurt.

Maternal celiac disease autoantibodies bind directly to syncytiotrophoblast and inhibit placental tissue transglutaminase activity

Directory of Open Access Journals (Sweden)

Robinson Nicola J

2009-02-01

Full Text Available Abstract Background Celiac disease (CD occurs in as many as 1 in 80 pregnant women and is associated with poor pregnancy outcome, but it is not known if this is an effect on maternal nutrient absorption or, alternatively, if the placenta is an autoimmune target. The major autoantigen, tissue transglutaminase (tTG, has previously been shown to be present in the maternal-facing syncytiotrophoblast plasma membrane of the placenta. Methods ELISA was used to demonstrate the presence of antibodies to tissue transglutaminase in a panel of CD sera. Immunohistochemistry was used to evaluate the binding of IgA autoantibodies from CD serum to term placenta. In addition, novel direct binding and activity assays were developed to mimic the in vivo exposure of the villous placenta to maternal autoantibody. Results and Discussion CD IgA autoantibodies located to the syncytial surface of the placenta significantly more than IgA antibodies in control sera (P Conclusion These data indicate that direct immune effects in untreated CD women may compromise placental function.

Electron transfer mechanisms, new applications, and performance of biocathode microbial fuel cells

KAUST Repository

Huang, Liping; Regan, John M.; Quan, Xie

2011-01-01

Broad application of microbial fuel cells (MFCs) requires low cost and high operational sustainability. Microbial-cathode MFCs, or cathodes using only bacterial catalysts (biocathodes), can satisfy these demands and have gained considerable attention in recent years. Achievements with biocathodes over the past 3-4. years have been particularly impressive not only with respect to the biological aspects but also the system-wide considerations related to electrode materials and solution chemistry. The versatility of biocathodes enables us to use not only oxygen but also contaminants as possible electron acceptors, allowing nutrient removal and bioremediation in conjunction with electricity generation. Moreover, biocathodes create opportunities to convert electrical current into microbially generated reduced products. While many new experimental results with biocathodes have been reported, we are still in the infancy of their engineering development. This review highlights the opportunities, limits, and challenges of biocathodes. © 2010 Elsevier Ltd.

Plasma membrane factor XIIIA transglutaminase activity regulates osteoblast matrix secretion and deposition by affecting microtubule dynamics.

Directory of Open Access Journals (Sweden)

Hadil F Al-Jallad

2011-01-01

Full Text Available Transglutaminase activity, arising potentially from transglutaminase 2 (TG2 and Factor XIIIA (FXIIIA, has been linked to osteoblast differentiation where it is required for type I collagen and fibronectin matrix deposition. In this study we have used an irreversible TG-inhibitor to 'block -and-track' enzyme(s targeted during osteoblast differentiation. We show that the irreversible TG-inhibitor is highly potent in inhibiting osteoblast differentiation and mineralization and reduces secretion of both fibronectin and type I collagen and their release from the cell surface. Tracking of the dansyl probe by Western blotting and immunofluorescence microscopy demonstrated that the inhibitor targets plasma membrane-associated FXIIIA. TG2 appears not to contribute to crosslinking activity on the osteoblast surface. Inhibition of FXIIIA with NC9 resulted in defective secretory vesicle delivery to the plasma membrane which was attributable to a disorganized microtubule network and decreased microtubule association with the plasma membrane. NC9 inhibition of FXIIIA resulted in destabilization of microtubules as assessed by cellular Glu-tubulin levels. Furthermore, NC9 blocked modification of Glu-tubulin into 150 kDa high-molecular weight Glu-tubulin form which was specifically localized to the plasma membrane. FXIIIA enzyme and its crosslinking activity were colocalized with plasma membrane-associated tubulin, and thus, it appears that FXIIIA crosslinking activity is directed towards stabilizing the interaction of microtubules with the plasma membrane. Our work provides the first mechanistic cues as to how transglutaminase activity could affect protein secretion and matrix deposition in osteoblasts and suggests a novel function for plasma membrane FXIIIA in microtubule dynamics.

Epitope-dependent functional effects of celiac disease autoantibodies on transglutaminase 2

DEFF Research Database (Denmark)

Hnida, Kathrin; Stamnaes, Jorunn; du Pré, M Fleur

2016-01-01

Transglutaminase 2 (TG2) is a Ca(2+)-dependent cross-linking enzyme involved in the pathogenesis of CD. We have previously characterized a panel of anti-TG2 mAbs generated from gut plasma cells of celiac patients and identified four epitopes (epitopes 1-4) located in the N-terminal part of TG2...... of epitope 1-targeting B cells to keep TG2 active and protected from oxidation might explain why generation of epitope 1-targeting plasma cells seems to be favored in celiac patients....

Dose-effect curves for electron-beam irradiation of some collection microbial strains

International Nuclear Information System (INIS)

Ferdes, O.; Dumitru, E.; Catargiu, L.; Ferdes, M.; Minea, R.; Oproiu, C.; Niculescu, A.

1994-01-01

There were electron-beam irradiated some microbial strains of B.subtilis ICA I-60 both in germination and in sporulated forms. The irradiation were performed at the IPTRD's electron accelerator at 6 MeV, and in the dose range between 0.1-5.0 kGy, at different dose-rate varying from 50 Gy/minute to 100 Gy/minute. The dosimetry was carried out by a PTW medical dosemeter. There were established the dose-effect relationships and curves, the inactivation dose (factor) and the optimum domain for electron-beam mutagenesis. There were obtained some mutant strains with 2-3.5 higher biosynthesis potential, which are in the IFC's collection. (Author)

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell.

Science.gov (United States)

Timmers, Ruud A; Rothballer, Michael; Strik, David P B T B; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

2012-04-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors.

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

Energy Technology Data Exchange (ETDEWEB)

Timmers, Ruud A.; Strik, David P.B.T.B.; Hamelers, Bert; Buisman, Cees [Wageningen Univ. (Netherlands). Sub-dept. of Environmental Technology; Rothballer, Michael; Hartmann, Anton [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Microbe-Plant Interactions; Engel, Marion; Schulz, Stephan; Schloter, Michael [Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Neuherberg (Germany). Dept. Terrestrial Ecogenetics

2012-04-15

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) were located on the root surfaces, but they were more abundant colonising the graphite granular electrode. Anaerobic cellulolytic bacteria dominated the area where most of the EAB were found, indicating that the current was probably generated via the hydrolysis of cellulose. Due to the presence of oxygen and nitrate, short-chain fatty acid-utilising denitrifiers were the major competitors for the electron donor. Acetate-utilising methanogens played a minor role in the competition for electron donor, probably due to the availability of graphite granules as electron acceptors. (orig.)

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

NARCIS (Netherlands)

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

The known two types of transglutaminases regulate immune and stress responses in white shrimp, Litopenaeus vannamei.

Science.gov (United States)

Chang, Chin-Chyuan; Chang, Hao-Che; Liu, Kuan-Fu; Cheng, Winton

2016-06-01

Transglutaminases (TGs) play critical roles in blood coagulation, immune responses, and other biochemical functions, which undergo post-translational remodeling such as acetylation, phosphorylation and fatty acylation. Two types of TG have been identified in white shrimp, Litopenaeus vannamei, and further investigation on their potential function was conducted by gene silencing in the present study. Total haemocyte count (THC), differential haemocyte count (DHC), phenoloxidase activity, respiratory bursts (release of superoxide anion), superoxide dismutase activity, transglutaminase (TG) activity, haemolymph clotting time, and phagocytic activity and clearance efficiency to the pathogen Vibrio alginolyticus were measured when shrimps were individually injected with diethyl pyrocarbonate-water (DEPC-H2O) or TG dsRNAs. In addition, haemolymph glucose and lactate, and haemocytes crustin, lysozyme, crustacean hyperglycemic hormone (CHH), transglutaminaseI (TGI), transglutaminaseII (TGII) and clotting protein (CP) mRNA expression were determined in the dsRNA injected shrimp under hypothermal stress. Results showed that TG activity, phagocytic activity and clearance efficiency were significantly decreased, but THC, hyaline cells (HCs) and haemolymph clotting time were significantly increased in the shrimp which received LvTGI dsRNA and LvTGI + LvTGII dsRNA after 3 days. However, respiratory burst per haemocyte was significantly decreased in only LvTGI + LvTGII silenced shrimp. In hypothermal stress studies, elevation of haemolymph glucose and lactate was observed in all treated groups, and were advanced in LvTGI and LvTGI + LvTGII silenced shrimp following exposure to 22 °C. LvCHH mRNA expression was significantly up-regulated, but crustin and lysozyme mRNA expressions were significantly down-regulated in LvTGI and LvTGI + LvTGII silenced shrimp; moreover, LvTGII was significantly increased, but LvTGI was significantly decreased in LvTGI silenced shrimp

Coeliac disease - clinical presentation and diagnosis by anti tissue transglutaminase antibodies titre in children

International Nuclear Information System (INIS)

Hussain, S.; Sabir, M.U.D.; Afzal, M.; Asghar, I.

2014-01-01

Objective: To study the spectrum of clinical presentation of coeliac disease and the role of IgA anti-tissue transglutaminase antibodies titer in the diagnosis and effect of gluten-free diet on such titers in children. Methods: The prospective study was conducted in the paediatric department of Combined Military Hospital, Kharian from Sep 2011 to Sep 2012. Children of 1-12 years of age presenting with chronic diarrhoea, malnutrition and failure to thrive were included regardless of gender, socioeconomic status, ethnicity and geographical distribution. Anti-tissue transglutaminase antibodies titers were done on enrolment. Patients with levels more than 30u/ml were enrolled. They were advised strict gluten-free diet for six months. These titers were repeated after six months to document the effect of gluten-free diet on these titers. Paediatric endoscopy and duodenal biopsy facilities were not available at the study site, so the response was monitored through titers. Data was analysed using SPSS-20. Results: Out of 61 patients with IgA levels more than 10 u/ml, 52 (85.24%) were found to have a positive (>30u/ml) anti-tissue transglutaminase antibodies titers with a mean value of 42.67+-7.60 U/ml. These 52 patients were then put on a trial of gluten-free diet for six months after which significant reduction in titer was noticed, with a mean value of 13.25+-2.59 U/ml. This reduction in titer was associated with marked clinical improvement and regression of symptoms. Frequency of different clinical features in descending order revealed that chronic diarrhoea, abdominal distension, iron deficiency anaemia, failure to thrive, pallor and rickets were present in 38 (73.1%), 30 (57.7%), 29 (55.8%), 29 (53.8%), 28 (53.8%) patients respectively. Conclusion: Chronic diarrhoea, failure to thrive, pallor, abdominal distention and iron deficiency anaemia were common modes of presentation. The antibodies were strongly positive in most of the cases. All children showed significant

Stay connected: Electrical conductivity of microbial aggregates.

Science.gov (United States)

Li, Cheng; Lesnik, Keaton Larson; Liu, Hong

2017-11-01

The discovery of direct extracellular electron transfer offers an alternative to the traditional understanding of diffusional electron exchange via small molecules. The establishment of electronic connections between electron donors and acceptors in microbial communities is critical to electron transfer via electrical currents. These connections are facilitated through conductivity associated with various microbial aggregates. However, examination of conductivity in microbial samples is still in its relative infancy and conceptual models in terms of conductive mechanisms are still being developed and debated. The present review summarizes the fundamental understanding of electrical conductivity in microbial aggregates (e.g. biofilms, granules, consortia, and multicellular filaments) highlighting recent findings and key discoveries. A greater understanding of electrical conductivity in microbial aggregates could facilitate the survey for additional microbial communities that rely on direct extracellular electron transfer for survival, inform rational design towards the aggregates-based production of bioenergy/bioproducts, and inspire the construction of new synthetic conductive polymers. Copyright © 2017 Elsevier Inc. All rights reserved.

Verfahren zur Herstellung von mit Transglutaminase vernetzten Proteinen pflanzlicher Herkunft, Proteingele und deren Verwendung

OpenAIRE

Schaefer, C.; Funda, E.

2003-01-01

WO2003017777 A UPAB: 20030505 NOVELTY - Production of vegetable protein crosslinked with transglutaminase (I) comprises (a) fractionating a protein extract, protein curds, protein concentrate, protein hydrolysate and/or protein isolate by centrifugation, ultrafiltration and/or precipitation and (b) crosslinking with 0.01-10 wt.% (I) at 0-60 deg. C. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for protein gel produced by crosslinking fractionated vegetable protein with (I). USE...

New method for characterizing electron mediators in microbial systems using a thin-layer twin-working electrode cell.

Science.gov (United States)

Hassan, Md Mahamudul; Cheng, Ka Yu; Ho, Goen; Cord-Ruwisch, Ralf

2017-01-15

Microbial biofilms are significant ecosystems where the existence of redox gradients drive electron transfer often via soluble electron mediators. This study describes the use of two interfacing working electrodes (WEs) to simulate redox gradients within close proximity (250µm) for the detection and quantification of electron mediators. By using a common counter and reference electrode, the potentials of the two WEs were independently controlled to maintain a suitable "voltage window", which enabled simultaneous oxidation and reduction of electron mediators as evidenced by the concurrent anodic and cathodic currents, respectively. To validate the method, the electrochemical properties of different mediators (hexacyanoferrate, HCF, riboflavin, RF) were characterized by stepwise shifting the "voltage window" (ranging between 25 and 200mV) within a range of potentials after steady equilibrium current of both WEs was established. The resulting differences in electrical currents between the two WEs were recorded across a defined potential spectrum (between -1V and +0.5V vs. Ag/AgCl). Results indicated that the technique enabled identification (by the distinct peak locations at the potential scale) and quantification (by the peak of current) of the mediators for individual species as well as in an aqueous mixture. It enabled a precise determination of mid-potentials of the externally added mediators (HCF, RF) and mediators produced by pyocyanin-producing Pseudomonas aeruginosa (WACC 91) culture. The twin working electrode described is particularly suitable for studying mediator-dependent microbial electron transfer processes or simulating redox gradients as they exist in microbial biofilms. Copyright © 2016 Elsevier B.V. All rights reserved.

Electron acceptors for anaerobic oxidation of methane drive microbial community structure and diversity in mud volcanoes.

Science.gov (United States)

Ren, Ge; Ma, Anzhou; Zhang, Yanfen; Deng, Ye; Zheng, Guodong; Zhuang, Xuliang; Zhuang, Guoqiang; Fortin, Danielle

2018-04-06

Mud volcanoes (MVs) emit globally significant quantities of methane into the atmosphere, however, methane cycling in such environments is not yet fully understood, as the roles of microbes and their associated biogeochemical processes have been largely overlooked. Here, we used data from high-throughput sequencing of microbial 16S rRNA gene amplicons from six MVs in the Junggar Basin in northwest China to quantify patterns of diversity and characterize the community structure of archaea and bacteria. We found anaerobic methanotrophs and diverse sulfate- and iron-reducing microbes in all of the samples, and the diversity of both archaeal and bacterial communities was strongly linked to the concentrations of sulfate, iron and nitrate, which could act as electron acceptors in anaerobic oxidation of methane (AOM). The impacts of sulfate/iron/nitrate on AOM in the MVs were verified by microcosm experiments. Further, two representative MVs were selected to explore the microbial interactions based on phylogenetic molecular ecological networks. The sites showed distinct network structures, key species and microbial interactions, with more complex and numerous linkages between methane-cycling microbes and their partners being observed in the iron/sulfate-rich MV. These findings suggest that electron acceptors are important factors driving the structure of microbial communities in these methane-rich environments. © 2018 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Modulation of transglutaminase 2 activity in H9c2 cells by PKC and PKA signalling: a role for transglutaminase 2 in cytoprotection

Science.gov (United States)

Almami, Ibtesam; Dickenson, John M; Hargreaves, Alan J; Bonner, Philip L R

2014-01-01

BACKGROUND AND PURPOSE Tissue transglutaminase (TG2) has been shown to mediate cell survival in many cell types. In this study, we investigated whether the role of TG2 in cytoprotection was mediated by the activation of PKA and PKC in cardiomyocyte-like H9c2 cells. EXPERIMENTAL APPROACH H9c2 cells were extracted following stimulation with phorbol-12-myristate-13-acetate (PMA) and forskolin. Transglutaminase activity was determined using an amine incorporating and a protein crosslinking assay. The presence of TG isoforms (TG1, 2, 3) was determined using Western blot analysis. The role of TG2 in PMA- and forskolin-induced cytoprotection was investigated by monitoring H2O2-induced oxidative stress in H9c2 cells. KEY RESULTS Western blotting showed TG2 >> TG1 protein expression but no detectable TG3. The amine incorporating activity of TG2 in H9c2 cells increased in a time and concentration-dependent manner following stimulation with PMA and forskolin. PMA and forskolin-induced TG2 activity was blocked by PKC (Ro 31-8220) and PKA (KT 5720 and Rp-8-Cl-cAMPS) inhibitors respectively. The PMA- and forskolin-induced increases in TG2 activity were attenuated by the TG2 inhibitors Z-DON and R283. Immunocytochemistry revealed TG2-mediated biotin-X-cadaverine incorporation into proteins and proteomic analysis identified known (β-tubulin) and novel (α-actinin) protein substrates for TG2. Pretreatment with PMA and forskolin reversed H2O2-induced decrease in MTT reduction and release of LDH. TG2 inhibitors R283 and Z-DON blocked PMA- and forskolin-induced cytoprotection. CONCLUSIONS AND IMPLICATIONS TG2 activity was stimulated via PKA- and PKC-dependent signalling pathways in H9c2 cells These results suggest a role for TG2 in cytoprotection induced by these kinases. PMID:24821315

Epidermal transglutaminase (TGase 3 is required for proper hair development, but not the formation of the epidermal barrier.

Directory of Open Access Journals (Sweden)

Susan John

Full Text Available Transglutaminases (TGase, a family of cross-linking enzymes present in most cell types, are important in events as diverse as cell-signaling and matrix stabilization. Transglutaminase 1 is crucial in developing the epidermal barrier, however the skin also contains other family members, in particular TGase 3. This isoform is highly expressed in the cornified layer, where it is believed to stabilize the epidermis and its reduction is implicated in psoriasis. To understand the importance of TGase 3 in vivo we have generated and analyzed mice lacking this protein. Surprisingly, these animals display no obvious defect in skin development, no overt changes in barrier function or ability to heal wounds. In contrast, hair lacking TGase 3 is thinner, has major alterations in the cuticle cells and hair protein cross-linking is markedly decreased. Apparently, while TGase 3 is of unique functional importance in hair, in the epidermis loss of TGase 3 can be compensated for by other family members.

Restructured fish product from white croacker (Micropogonias furnieri mince using microbial transglutaminas

Directory of Open Access Journals (Sweden)

Alex Augusto Gonçalves

2010-08-01

Full Text Available This study aimed at determining the influence of three concentrations of commercial transglutaminase enzyme in restructured fillet of minced fish from white croacker (Micropogonias furnieri, one of the four marine species with notability in Brazil. The restructured fillet developed had advantages when compared to traditional fillet, such as absence of spine and less flavour intensity (washes cycles. Washing process for white croacker mince was compared with five clarification agents: water (control, phosphoric acid (H3PO4, sodium chloride (NaCl, calcium carbonate (CaCO3 and sodium bicarbonate (NaHCO3. The higher quality product (whiteness was obtained with calcium carbonate washes. Three concentrations (1.5, 1.0 and 0.5% of microbial transglutaminase MGTase (Active TG-B %v/v and Active TG-BP %w/w were compared, in order to produce fish restructured product (boneless fillet. The concentration of 1.5% (both enzymes, produced better results. The restructured products were compared by sensory analysis and showed better sensory parameters (appearance, odour, flavour and texture samples treated with Active TG-B (solution form.Este estudo teve como objetivo determinar a influência de três concentrações de enzima transglutaminase comercial em filés reestruturado a partir de polpa de corvina (Micropogonias furnieri, uma das quatro espécies marinhas notáveis no Brasil. O filé reestruturado desenvolvido tem vantagens quando comparado aos filés tradicionais, tais como, a ausência da espinhas e sabor menos intenso (ciclos de lavagens. O processo de lavagem da polpa de corvina foi comparado com cinco agentes clarificantes: água (controle, ácido fosfórico (H3PO4, cloreto de sódio (NaCl, carbonato de cálcio (CaCO3 e bicarbonato de sódio (NaHCO3. O produto de qualidade superior (mais branco foi obtido com a lavagem com carbonato de cálcio. Três concentrações (1,5%, 1,0% e 0,5% de transglutaminase microbiana (Activa TG-B % v/v e Activa TG

Pluripotency and a secretion mechanism of Drosophila transglutaminase.

Science.gov (United States)

Shibata, Toshio; Kawabata, Shun-Ichiro

2018-03-01

Transglutaminase (TG) catalyses the formation of an isopeptide bond between glutamine and lysine residues and amine incorporation into specific glutamine residues. TG is conserved in all metazoans and functions both intracellularly and extracellularly. Here we review the existing knowledge of Drosophila TG with an emphasis on its pluripotency: Drosophila TG (i) plays a key role in cuticular morphogenesis, haemolymph coagulation, and entrapment against invading pathogens, (ii) suppresses the immune deficiency pathway to enable immune tolerance against commensal bacteria through the incorporation of polyamines into the nuclear factor-κB-like transcription factor Relish as well as through the protein-protein cross-linking of Relish, (iii) forms a physical matrix in the gut through cross-linking of chitin-binding proteins and (iv) is involved in the maintenance of homeostasis in microbiota in the gut. Moreover, we review the evidence that TG-A, one of alternative splicing-derived isoforms of Drosophila TG, is secreted through an endoplasmic reticulum/Golgi-independent pathway involving exosomes and fatty acylations.

Influence of Bicarbonate, Sulfate, and Electron Donors on Biological reduction of Uranium and Microbial Community Composition

Energy Technology Data Exchange (ETDEWEB)

Luo, Wensui [ORNL; Zhou, Jizhong [ORNL; Wu, Weimin [ORNL; Yan, Tingfen [ORNL; Criddle, Craig [ORNL; Jardine, Philip M [ORNL; Gu, Baohua [ORNL

2007-01-01

A microcosm study was performed to investigate the effect of ethanol and acetate on uranium(VI) biological reduction and microbial community changes under various geochemical conditions. Each microcosm contained an uranium-contaminated sediment (up to 2.8 g U/kg) suspended in buffer with bicarbonate at concentrations of either 1 mM or 40 mM and sulfate at either 1.1 or 3.2 mM. Ethanol or acetate was used as an electron donor. Results indicate that ethanol yielded in significantly higher U(VI) reduction rates than acetate. A low bicarbonate concentration (1 mM) was favored for U(VI) bioreduction to occur in sediments, but high concentrations of bicarbonate (40 mM) and sulfate (3.2 mM) decreased the reduction rates of U(VI). Microbial communities were dominated by species from the Geothrix genus and Proteobacteria phylum in all microcosms. However, species in the Geobacteraceae family capable of reducing U(VI) were significantly enriched by ethanol and acetate in low bicarbonate buffer. Ethanol increased the population of unclassified Desulfuromonales, while acetate increased the population of Desulfovibrio. Additionally, species in the Geobacteraceae family were not enriched in high bicarbonate buffer, but the Geothrix and the unclassified Betaproteobacteria species were enriched. This study concludes that ethanol could be a better electron donor than acetate for reducing U(VI) under given experimental conditions, and electron donor and geoundwater geochemistry alter microbial communities responsible for U(VI) reduction.

Influence of bicarbonate, sulfate, and electron donors on biological reduction of uranium and microbial community composition

Energy Technology Data Exchange (ETDEWEB)

Luo Wensui [Oak Ridge Inst. for Science and Education, TN (United States); Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Wu Wei-Min; Criddle, C.S. [Stanford Univ., CA (United States). Dept. of Civil and Environmental Engineering; Yan Tingfen [Oak Ridge Inst. for Science and Education, TN (United States); Jardine, P.M.; Gu Baohua [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Zhou Jizhong [Oklahoma Univ., Norman, OK (United States). Dept. of Botany and Microbiology

2007-12-15

A microcosm study was performed to investigate the effect of ethanol and acetate on uranium(VI) biological reduction and microbial community changes under various geochemical conditions. Each microcosm contained an uranium-contaminated sediment (up to 2.8 g U/kg) suspended in buffer with bicarbonate at concentrations of either 1 or 40 mM and sulfate at either 1.1 or 3.2 mM. Ethanol or acetate was used as an electron donor. Results indicate that ethanol yielded in significantly higher U(VI) reduction rates than acetate. A low bicarbonate concentration (1 mM) was favored for U(VI) bioreduction to occur in sediments, but high concentrations of bicarbonate (40 mM) and sulfate (3.2 mM) decreased the reduction rates of U(VI). Microbial communities were dominated by species from the Geothrix genus and Proteobacteria phylum in all microcosms. However, species in the Geobacteraceae family capable of reducing U(VI) were significantly enriched by ethanol and acetate in low-bicarbonate buffer. Ethanol increased the population of unclassified Desulfuromonales, while acetate increased the population of Desulfovibrio. Additionally, species in the Geobacteraceae family were not enriched in high-bicarbonate buffer, but the Geothrix and the unclassified Betaproteobacteria species were enriched. This study concludes that ethanol could be a better electron donor than acetate for reducing U(VI) under given experimental conditions, and electron donor and groundwater geochemistry alter microbial communities responsible for U(VI) reduction. (orig.)

Hydrolysis of surimi wastewater for production of transglutaminase by Enterobacter sp. C2361 and Providencia sp. C1112.

Science.gov (United States)

H-Kittikun, Aran; Bourneow, Chaiwut; Benjakul, Soottawat

2012-12-01

Surimi wastewater (SWW) is an industrial wastewater, released during the washing step of surimi preparation from minced fish, that causes environmental problem. In this study, SWW produced from ornate threadfin bream (Nemipterus hexodon) was hydrolysed and used to cultivate Enterobacter sp. C2361 and Providencia sp. C1112 for the production of microbial transglutaminase (MTGase, EC 2.3.2.13). The SWW was repeatedly used to wash the fish mince that gained a final protein content of 3.20% (w/v). The commercial protease, Delvolase was the most appropriate protease used to produce fish protein hydrolysate (FPH) from SWW. The FPH at 40% degree of hydrolysis was used instead of a peptone portion in the SPY medium (3.0% starch, 2.0% peptone, 0.2% yeast extract, 0.2% MgSO(4), 0.2% K(2)HPO(4) and 0.2% KH(2)HPO(4), pH 7.0) to cultivate the tested strains at 37°C, shaking speed at 150rpm. Providencia sp. C1112 produced higher MTGase activity (1.78±0.05U/ml) than Streptoverticillium mobaraense (1.61±0.02U/ml) at 18h of cultivation in FPH medium. On the other hand, the Enterobacter sp. C2361 produced lower MTGase activity (1.18±0.03U/ml). Copyright © 2012 Elsevier Ltd. All rights reserved.

A Novel Mutation in the Transglutaminase-1 Gene in an Autosomal Recessive Congenital Ichthyosis Patient

Directory of Open Access Journals (Sweden)

D. Vaigundan

2014-01-01

Full Text Available Structure-function implication on a novel homozygous Trp250/Gly mutation of transglutaminase-1 (TGM1 observed in a patient of autosomal recessive congenital ichthyosis is invoked from a bioinformatics analysis. Structural consequences of this mutation are hypothesized in comparison to homologous enzyme human factor XIIIA accepted as valid in similar structural analysis and are projected as guidelines for future studies at an experimental level on TGM1 thus mutated.

The effect of flavin electron shuttles in microbial fuel cells current production

Energy Technology Data Exchange (ETDEWEB)

Velasquez-Orta, Sharon B. [Newcastle Univ., Newcastle upon Tyne (United Kingdom). School of Civil Engineering and Geosciences; Newcastle Univ., Newcastle upon Tyne (United Kingdom). School of Chemical Engineering and Advanced Materials; Head, Ian M.; Curtis, Thomas P. [Newcastle Univ., Newcastle upon Tyne (United Kingdom). School of Civil Engineering and Geosciences; Scott, Keith [Newcastle Univ., Newcastle upon Tyne (United Kingdom). School of Chemical Engineering and Advanced Materials; Lloyd, Jonathan R.; Canstein, Harald von [Manchester Univ. (United Kingdom). School of Earth, Atmospheric and Environmental Sciences

2010-02-15

The effect of electron shuttles on electron transfer to microbial fuel cell (MFC) anodes was studied in systems where direct contact with the anode was precluded. MFCs were inoculated with Shewanella cells, and flavins used as the electron shuttling compound. In MFCs with no added electron shuttles, flavin concentrations monitored in the MFCs' bulk liquid increased continuously with FMN as the predominant flavin. The maximum concentrations were 0.6 {mu}M for flavin mononucleotide and 0.2 {mu}M for riboflavin. In MFCs with added flavins, micro-molar concentrations were shown to increase current and power output. The peak current was at least four times higher in MFCs with high concentrations of flavins (4.5-5.5 {mu}M) than in MFCs with low concentrations (0.2-0.6 {mu}M). Although high power outputs (around 150 mW/m{sup 2}) were achieved in MFCs with high concentrations of flavins, a Clostridium-like bacterium along with other reactor limitations affected overall coulombic efficiencies (CE) obtained, achieving a maximum CE of 13%. Electron shuttle compounds (flavins) permitted bacteria to utilise a remote electron acceptor (anode) that was not accessible to the cells allowing current production until the electron donor (lactate) was consumed. (orig.)

Phage display selection of efficient glutamine-donor substrate peptides for transglutaminase 2.

Science.gov (United States)

Keresztessy, Zsolt; Csosz, Eva; Hársfalvi, Jolán; Csomós, Krisztián; Gray, Joe; Lightowlers, Robert N; Lakey, Jeremy H; Balajthy, Zoltán; Fésüs, László

2006-11-01

Understanding substrate specificity and identification of natural targets of transglutaminase 2 (TG2), the ubiquitous multifunctional cross-linking enzyme, which forms isopeptide bonds between protein-linked glutamine and lysine residues, is crucial in the elucidation of its physiological role. As a novel means of specificity analysis, we adapted the phage display technique to select glutamine-donor substrates from a random heptapeptide library via binding to recombinant TG2 and elution with a synthetic amine-donor substrate. Twenty-six Gln-containing sequences from the second and third biopanning rounds were susceptible for TG2-mediated incorporation of 5-(biotinamido)penthylamine, and the peptides GQQQTPY, GLQQASV, and WQTPMNS were modified most efficiently. A consensus around glutamines was established as pQX(P,T,S)l, which is consistent with identified substrates listed in the TRANSDAB database. Database searches showed that several proteins contain peptides similar to the phage-selected sequences, and the N-terminal glutamine-rich domain of SWI1/SNF1-related chromatin remodeling proteins was chosen for detailed analysis. MALDI/TOF and tandem mass spectrometry-based studies of a representative part of the domain, SGYGQQGQTPYYNQQSPHPQQQQPPYS (SnQ1), revealed that Q(6), Q(8), and Q(22) are modified by TG2. Kinetic parameters of SnQ1 transamidation (K(M)(app) = 250 microM, k(cat) = 18.3 sec(-1), and k(cat)/K(M)(app) = 73,200) classify it as an efficient TG2 substrate. Circular dichroism spectra indicated that SnQ1 has a random coil conformation, supporting its accessibility in the full-length parental protein. Added together, here we report a novel use of the phage display technology with great potential in transglutaminase research.

A specific colorimetric assay for measuring transglutaminase 1 and factor XIII activities.

Science.gov (United States)

Hitomi, Kiyotaka; Kitamura, Miyako; Alea, Mileidys Perez; Ceylan, Ismail; Thomas, Vincent; El Alaoui, Saïd

2009-11-15

Transglutaminase (TGase) is an enzyme that catalyzes both isopeptide cross-linking and incorporation of primary amines into proteins. Eight TGases have been identified in humans, and each of these TGases has a unique tissue distribution and physiological significance. Although several assays for TGase enzymatic activity have been reported, it has been difficult to establish an assay for discriminating each of these different TGase activities. Using a random peptide library, we recently identified the preferred substrate sequences for three major TGases: TGase 1, TGase 2, and factor XIII. In this study, we use these substrates in specific tests for measuring the activities of TGase 1 and factor XIII.

Microbial Anaerobic Ammonium Oxidation Under Iron Reducing Conditions, Alternative Electron Acceptors

Science.gov (United States)

Ruiz-Urigüen, M.; Jaffe, P. R.

2015-12-01

Autotrophic Acidimicrobiaceae-bacterium named A6 (A6), part of the Actinobacteria phylum have been linked to anaerobic ammonium (NH4+) oxidation under iron reducing conditions. These organisms obtain their energy by oxidizing NH4+ and transferring the electrons to a terminal electron acceptor (TEA). Under environmental conditions, the TEAs are iron oxides [Fe(III)], which are reduced to Fe(II), this process is known as Feammox. Our studies indicate that alternative forms of TEAs can be used by A6, e.g. iron rich clays (i.e. nontronite) and electrodes in bioelectrochemical systems such as Microbial Electrolysis Cells (MECs), which can sustain NH4+removal and A6 biomass production. Our results show that nontronite can support Feammox and promote bacterial cell production. A6 biomass increased from 4.7 x 104 to 3.9 x 105 cells/ml in 10 days. Incubations of A6 in nontronite resulted in up to 10 times more NH4+ removal and 3 times more biomass production than when ferrihydrite is used as the Fe(III) source. Additionally, Fe in nontronite can be reoxidized by aeration and A6 can reutilize it; however, Fe is still finite in the clay. In contrast, in MECs, A6 harvest electrons from NH4+ and use an anode as an unlimited TEA, as a result current is produced. We operated multiple MECs in parallel using a single external power source, as described by Call & Logan (2011). MECs were run with an applied voltage of 0.7V and different growing mediums always containing initial 5mM NH4+. Results show that current production is favored when anthraquinone-2,6-disulfonate (AQDS), an electron shuttled, is present in the medium as it facilitates the transfer of electrons from the bacterial cell to the anode. Additionally, A6 biomass increased from 1 x 104 to 9.77 x 105cells/ml in 14 days of operation. Due to Acidimicrobiaceae-bacterium A6's ability to use various TEAs, MECs represent an alternative, iron-free form, for optimized biomass production of A6 and its application in NH4

Electron shuttles in biotechnology.

Science.gov (United States)

Watanabe, Kazuya; Manefield, Mike; Lee, Matthew; Kouzuma, Atsushi

2009-12-01

Electron-shuttling compounds (electron shuttles [ESs], or redox mediators) are essential components in intracellular electron transfer, while microbes also utilize self-produced and naturally present ESs for extracellular electron transfer. These compounds assist in microbial energy metabolism by facilitating electron transfer between microbes, from electron-donating substances to microbes, and/or from microbes to electron-accepting substances. Artificially supplemented ESs can create new routes of electron flow in the microbial energy metabolism, thereby opening up new possibilities for the application of microbes to biotechnology processes. Typical examples of such processes include halogenated-organics bioremediation, azo-dye decolorization, and microbial fuel cells. Herein we suggest that ESs can be applied widely to create new microbial biotechnology processes.

Coeliac disease autoantibodies mediate significant inhibition of tissue transglutaminase.

LENUS (Irish Health Repository)

Byrne, Greg

2012-02-01

The detection of antibodies directed against tissue transglutaminase (tTG) in serum is a sensitive and specific test for suspected coeliac disease. tTG is a ubiquitous, multifunctional enzyme that has been implicated in many important physiological processes as well as the site-specific deamidation of glutamine residues in gluten-derived peptides. This modification of gluten peptides facilitates their binding to HLA-DQ2, which results in amplification of the T-cell response to gluten. The purpose of this study was to investigate the possibility that patient IgA autoantibodies directed against tTG interfere with the crosslinking activity of the enzyme. IgA autoantibodies against tTG were isolated\\/depleted from patient serum and tested for their capacity to interfere with tTG activity in vitro using a sensitive fluorescence-based activity assay. We have demonstrated that autoantibodies cause significant inhibition of tTG-mediated crosslinking at equimolar and 2:1 ratios of antibody to enzyme.

Effects of gamma ray and electron beam irradiation on reduction of microbial load and antioxidant properties of Chum-Hed-Thet (Cassia alata (L.) Roxb.)

Science.gov (United States)

Prakhongsil, P.; Pewlong, W.; Sajjabut, S.; Chookaew, S.

2017-06-01

Considering the growing demands of herbal medicines, Cassia alata (L.) Roxb. has been reported to have various phytochemical activities. It has also been called in Thai as Chum-Hed-Thet. In this study, C. alata (L.) Roxb. powder were exposed to gamma and electron beam irradiation at doses of 0, 5, 10, 15 and 20 kGy. At the dose of 10 kGy, both of gamma and electron beam irradiation were sufficient in reducing microbial load of irradiated samples as specified in Thai pharmacopoeia (2005). These include the total aerobic microbial count of bacteria of 0.05). Therefore, both of radiation by gamma ray or electron beam at 10 kGy was sufficient in elimination of microbial flora and did not significantly affected the total phenolic content and antioxidant activities of C. alata (L.) Roxb.

β2-adrenoceptor-induced modulation of transglutaminase 2 transamidase activity in cardiomyoblasts.

Science.gov (United States)

Vyas, Falguni S; Nelson, Carl P; Freeman, Fiona; Boocock, David J; Hargreaves, Alan J; Dickenson, John M

2017-10-15

Tissue transglutaminase 2 (TG2) is modulated by protein kinase A (PKA) mediated phosphorylation: however, the precise mechanism(s) of its modulation by G-protein coupled receptors coupled to PKA activation are not fully understood. In the current study we investigated the potential regulation of TG2 activity by the β 2 -adrenoceptor in rat H9c2 cardiomyoblasts. Transglutaminase transamidation activity was assessed using amine-incorporating and protein cross-linking assays. TG2 phosphorylation was determined via immunoprecipitation and Western blotting. The long acting β 2 -adrenoceptor agonist formoterol induced time- and concentration-dependent increases in TG2 transamidation. Increases in TG2 activity were reduced by the TG2 inhibitors Z-DON (Benzyloxycarbonyl-(6-Diazo-5-oxonorleucinyl)-L-valinyl-L-prolinyl-L-leucinmethylester) and R283 ((1,3,dimethyl-2[2-oxo-propyl]thio)imidazole chloride). Responses to formoterol were blocked by pharmacological inhibition of PKA, extracellular signal-regulated kinase 1 and 2 (ERK1/2), or phosphatidylinositol 3-kinase (PI-3K) signalling. Furthermore, the removal of extracellular Ca 2+ also attenuated formoterol-induced TG2 activation. Fluorescence microscopy demonstrated TG2-induced biotin-X-cadaverine incorporation into proteins. Formoterol increased the levels of TG2-associated phosphoserine and phosphothreonine, which were blocked by inhibition of PKA, ERK1/2 or PI-3K signalling. Subsequent proteomic analysis identified known (e.g. lactate dehydrogenase A chain) and novel (e.g. Protein S100-A6) protein substrates for TG2. Taken together, the data obtained suggest that β 2 -adrenoceptor-induced modulation of TG2 represents a novel paradigm in β 2 -adrenoceptor cell signalling, expanding the repertoire of cellular functions responsive to catecholamine stimulation. Copyright © 2017 Elsevier B.V. All rights reserved.

Electronic Nose Technology to Measure Soil Microbial Activity and Classify Soil Metabolic Status

OpenAIRE

Fabrizio De Cesare; Elena Di Mattia; Simone Pantalei; Emiliano Zampetti; Vittorio Vinciguerra; Antonella Macagnano

2011-01-01

The electronic nose (E-nose) is a sensing technology that has been widely used to monitor environments in the last decade. In the present study, the capability of an E-nose, in combination with biochemical and microbiological techniques, of both detecting the microbial activity and estimating the metabolic status of soil ecosystems, was tested by measuring on one side respiration, enzyme activities and growth of bacteria in natural but simplified soil ecosystems over 23 days of incubation thr...

Humin as an electron donor for enhancement of multiple microbial reduction reactions with different redox potentials in a consortium.

Science.gov (United States)

Zhang, Dongdong; Zhang, Chunfang; Xiao, Zhixing; Suzuki, Daisuke; Katayama, Arata

2015-02-01

A solid-phase humin, acting as an electron donor, was able to enhance multiple reductive biotransformations, including dechlorination of pentachlorophenol (PCP), dissimilatory reduction of amorphous Fe (III) oxide (FeOOH), and reduction of nitrate, in a consortium. Humin that was chemically reduced by NaBH4 served as an electron donor for these microbial reducing reactions, with electron donating capacities of 0.013 mmol e(-)/g for PCP dechlorination, 0.15 mmol e(-)/g for iron reduction, and 0.30 mmol e(-)/g for nitrate reduction. Two pairs of oxidation and reduction peaks within the humin were detected by cyclic voltammetry analysis. 16S rRNA gene sequencing-based microbial community analysis of the consortium incubated with different terminal electron acceptors, suggested that Dehalobacter sp., Bacteroides sp., and Sulfurospirillum sp. were involved in the PCP dechlorination, dissimilatory iron reduction, and nitrate reduction, respectively. These findings suggested that humin functioned as a versatile redox mediator, donating electrons for multiple respiration reactions with different redox potentials. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Tissue transglutaminase inhibits the TRPV5-dependent calcium transport in an N-glycosylation-dependent manner

DEFF Research Database (Denmark)

Boros, Sandor; Xi, Qi; Dimke, Henrik Anthony

2011-01-01

Tissue transglutaminase (tTG) is a multifunctional Ca(2+)-dependent enzyme, catalyzing protein crosslinking. The transient receptor potential vanilloid (TRPV) family of cation channels was recently shown to contribute to the regulation of TG activities in keratinocytes and hence skin barrier form......, these observations imply that tTG is a novel extracellular enzyme inhibiting the activity of TRPV5. The inhibition of TRPV5 occurs in an N-glycosylation-dependent manner, signifying a common final pathway by which distinct extracellular factors regulate channel activity....

Digestibility of transglutaminase cross-linked caseinate versus native caseinate in an in vitro multicompartmental model simulating young child and adult gastrointestinal conditions

NARCIS (Netherlands)

Havenaar, R.; Jong, A. de; Koenen, M.E.; Bilsen, J. van; Janssen, A.M.; Labij, E.; Westerbeek, H.J.M.

2013-01-01

Aim of this study was to investigate the digestion of transglutaminase cross-linked caseinate (XLC) versus native caseinate (NC) in solution and in cheese spread under digestive conditions for adults and children mimicked in a gastrointestinal model. Samples were collected for gel electrophoresis

Influence of Gamma and Electron Beam Irradiation on Microbial Load of Pueraria mirifica

International Nuclear Information System (INIS)

Eamsiri, J.; Pewlong, W.; Sajjabut, S.; Chookaew, S.

2014-01-01

The purpose of this study is to investigate the effect of gamma ray and electron beam on the microbial load of Pueraria mirifica at selected storage period post exposure to irradiation. The samples were irradiated at 0, 5, 10, 15 and 20 kGy and then analyzed for the total bacteria, total yeast and mold, and the presence of Coliform bacteria, Escherichia coli, Salmonella sp., Bacillus cereus and Clostridium perfringens after 0, 3, 6, 9 and 12 months of storage. Results demonstrated that both irradiation techniques significantly reduced microbial contamination. As the reduction in bacteria count decreased linearly with the absorbed dose, the dose of 5 kGy was found to be sufficient in eliminating pathogens with the total bacteria count decreased to the value accepted by the Thai Industrial standard 1441/2552. In addition, we found that total bacteria, total yeast and mold and pathogens did not change significantly after storage up to 12 months post irradiation.

Controlo da alergenicidade do soro de leite por reticulação com transglutaminase

OpenAIRE

Aguiar, Sara Sofia de Jesus

2017-01-01

As alergias alimentares estão classificadas entre os maiores problemas de saúde humana pela OMS. O soro de leite apresenta uma mistura de proteínas, contendo todos os aminoácidos essenciais sendo a β-lactoglobulina a proteína alergénica dominante. Devido à elevada taxa de consumo do soro de leite é fundamental encontrar uma metodologia que reduza o potencial alergénico das proteínas do soro sem as remover. A reticulação de proteínas pela transglutaminase é uma técnica recente que permit...

Quality not quantity for transglutaminase antibody 2: the performance of an endomysial and tissue transglutaminase test in screening coeliac disease remains stable over time.

Science.gov (United States)

Swallow, K; Wild, G; Sargur, R; Sanders, D S; Aziz, I; Hopper, A D; Egner, W

2013-01-01

National Institute of Clinical Excellence (NICE) and European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) guidance for the diagnosis of coeliac disease has been published. However, there is some controversy regarding the advice on the use of stratifying levels of immunoglobulin (IgA) tissue transglutaminase antibody (TG2) test positivity in the absence of test standardization and the vagueness of the indication to test equivocal samples. Using repeat service audit, we demonstrate that a combination of TG2 followed by IgA endomysial antibodies (EMA) is the best strategy for all degrees of mucosal abnormality using our test combination. Reliance upon immunoassay titre is not as effective, and cannot be applied consistently across populations in the absence of assay standardization. Guidelines advocating the use of tests should involve experts in laboratory diagnostics and external quality assurance to ensure that errors of generalization do not occur and that test performance is achievable in routine diagnostic use. © 2012 British Society for Immunology.

Multiple paths of electron flow to current in microbial electrolysis cells fed with low and high concentrations of propionate

KAUST Repository

Rao, Hari Ananda; Katuri, Krishna; Gorron, Eduardo; Logan, Bruce E.; Saikaly, Pascal

2016-01-01

Microbial electrolysis cells (MECs) provide a viable approach for bioenergy generation from fermentable substrates such as propionate. However, the paths of electron flow during propionate oxidation in the anode of MECs are unknown. Here, the paths

Multiple paths of electron flow to current in microbial electrolysis cells fed with low and high concentrations of propionate

KAUST Repository

Rao, Hari Ananda

2016-03-03

Microbial electrolysis cells (MECs) provide a viable approach for bioenergy generation from fermentable substrates such as propionate. However, the paths of electron flow during propionate oxidation in the anode of MECs are unknown. Here, the paths of electron flow involved in propionate oxidation in the anode of two-chambered MECs were examined at low (4.5 mM) and high (36 mM) propionate concentrations. Electron mass balances and microbial community analysis revealed that multiple paths of electron flow (via acetate/H2 or acetate/formate) to current could occur simultaneously during propionate oxidation regardless of the concentration tested. Current (57–96 %) was the largest electron sink and methane (0–2.3 %) production was relatively unimportant at both concentrations based on electron balances. At a low propionate concentration, reactors supplemented with 2-bromoethanesulfonate had slightly higher coulombic efficiencies than reactors lacking this methanogenesis inhibitor. However, an opposite trend was observed at high propionate concentration, where reactors supplemented with 2-bromoethanesulfonate had a lower coulombic efficiency and there was a greater percentage of electron loss (23.5 %) to undefined sinks compared to reactors without 2-bromoethanesulfonate (11.2 %). Propionate removal efficiencies were 98 % (low propionate concentration) and 78 % (high propionate concentration). Analysis of 16S rRNA gene pyrosequencing revealed the dominance of sequences most similar to Geobacter sulfurreducens PCA and G. sulfurreducens subsp. ethanolicus. Collectively, these results provide new insights on the paths of electron flow during propionate oxidation in the anode of MECs fed with low and high propionate concentrations.

Microbial fuel cell operation using monoazo and diazo dyes as terminal electron acceptor for simultaneous decolourisation and bioelectricity generation.

Science.gov (United States)

Oon, Yoong-Sin; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Oon, Yoong-Ling; Lehl, Harvinder Kaur; Thung, Wei-Eng; Nordin, Noradiba

2017-03-05

Monoazo and diazo dyes [New coccine (NC), Acid orange 7 (AO7), Reactive red 120 (RR120) and Reactive green 19 (RG19)] were employed as electron acceptors in the abiotic cathode of microbial fuel cell. The electrons and protons generated from microbial organic oxidation at the anode which were utilized for electrochemical azo dye reduction at the cathodic chamber was successfully demonstrated. When NC was employed as the electron acceptor, the chemical oxygen demand (COD) removal and dye decolourisation efficiencies obtained at the anodic and cathodic chamber were 73±3% and 95.1±1.1%, respectively. This study demonstrated that the decolourisation rates of monoazo dyes were ∼50% higher than diazo dyes. The maximum power density in relation to NC decolourisation was 20.64mW/m 2 , corresponding to current density of 120.24mA/m 2 . The decolourisation rate and power output of different azo dyes were in the order of NC>AO7>RR120>RG19. The findings revealed that the structure of dye influenced the decolourisation and power performance of MFC. Azo dye with electron-withdrawing group at para substituent to azo bond would draw electrons from azo bond; hence the azo dye became more electrophilic and more favourable for dye reduction. Copyright © 2016 Elsevier B.V. All rights reserved.

Are Microbial Nanowires Responsible for Geoelectrical Changes at Hydrocarbon Contaminated Sites?

Science.gov (United States)

Hager, C.; Atekwana, E. A.; Gorby, Y. A.; Duris, J. W.; Allen, J. P.; Atekwana, E. A.; Ownby, C.; Rossbach, S.

2007-05-01

Significant advances in near-surface geophysics and biogeophysics in particular, have clearly established a link between geoelectrical response and the growth and enzymatic activities of microbes in geologic media. Recent studies from hydrocarbon contaminated sites suggest that the activities of distinct microbial populations, specifically syntrophic, sulfate reducing, and dissimilatory iron reducing microbial populations are a contributing factor to elevated sediment conductivity. However, a fundamental mechanistic understanding of the processes and sources resulting in the measured electrical response remains uncertain. The recent discovery of bacterial nanowires and their electron transport capabilities suggest that if bacterial nanowires permeate the subsurface, they may in part be responsible for the anomalous conductivity response. In this study we investigated the microbial population structure, the presence of nanowires, and microbial-induced alterations of a hydrocarbon contaminated environment and relate them to the sediments' geoelectrical response. Our results show that microbial communities varied substantially along the vertical gradient and at depths where hydrocarbons saturated the sediments, ribosomal intergenic spacer analysis (RISA) revealed signatures of microbial communities adapted to hydrocarbon impact. In contrast, RISA profiles from a background location showed little community variations with depth. While all sites showed evidence of microbial activity, a scanning electron microscope (SEM) study of sediment from the contaminated location showed pervasive development of "nanowire-like structures" with morphologies consistent with nanowires from laboratory experiments. SEM analysis suggests extensive alteration of the sediments by microbial Activity. We conclude that, excess organic carbon (electron donor) but limited electron acceptors in these environments cause microorganisms to produce nanowires to shuttle the electrons as they seek for

Microbial fuel cell operation using monoazo and diazo dyes as terminal electron acceptor for simultaneous decolourisation and bioelectricity generation

International Nuclear Information System (INIS)

Oon, Yoong-Sin; Ong, Soon-An; Ho, Li-Ngee; Wong, Yee-Shian; Oon, Yoong-Ling; Lehl, Harvinder Kaur; Thung, Wei-Eng; Nordin, Noradiba

2017-01-01

Highlights: • Monoazo and diazo dyes were used as electron acceptor in the abiotic cathode of MFC. • Simultaneous decolourisation and bioelectricity generation were achieved. • Azo dye structures influenced the decolourisation performance. • Positive relation between decolourisation rate and power performance. - Abstract: Monoazo and diazo dyes [New coccine (NC), Acid orange 7 (AO7), Reactive red 120 (RR120) and Reactive green 19 (RG19)] were employed as electron acceptors in the abiotic cathode of microbial fuel cell. The electrons and protons generated from microbial organic oxidation at the anode which were utilized for electrochemical azo dye reduction at the cathodic chamber was successfully demonstrated. When NC was employed as the electron acceptor, the chemical oxygen demand (COD) removal and dye decolourisation efficiencies obtained at the anodic and cathodic chamber were 73 ± 3% and 95.1 ± 1.1%, respectively. This study demonstrated that the decolourisation rates of monoazo dyes were ∼50% higher than diazo dyes. The maximum power density in relation to NC decolourisation was 20.64 mW/m"2, corresponding to current density of 120.24 mA/m"2. The decolourisation rate and power output of different azo dyes were in the order of NC > AO7 > RR120 > RG19. The findings revealed that the structure of dye influenced the decolourisation and power performance of MFC. Azo dye with electron-withdrawing group at para substituent to azo bond would draw electrons from azo bond; hence the azo dye became more electrophilic and more favourable for dye reduction.

Microbial fuel cell operation using monoazo and diazo dyes as terminal electron acceptor for simultaneous decolourisation and bioelectricity generation

Energy Technology Data Exchange (ETDEWEB)

Oon, Yoong-Sin [Water Research Group (WAREG), School of Environmental Engineering, Universiti Malaysia Perlis, 02600, Arau, Perlis (Malaysia); Ong, Soon-An, E-mail: ongsoonan@yahoo.com [Water Research Group (WAREG), School of Environmental Engineering, Universiti Malaysia Perlis, 02600, Arau, Perlis (Malaysia); Ho, Li-Ngee [School of Materials Engineering, Universiti Malaysia Perlis, 02600, Arau, Perlis (Malaysia); Wong, Yee-Shian; Oon, Yoong-Ling; Lehl, Harvinder Kaur; Thung, Wei-Eng [Water Research Group (WAREG), School of Environmental Engineering, Universiti Malaysia Perlis, 02600, Arau, Perlis (Malaysia); Nordin, Noradiba [School of Materials Engineering, Universiti Malaysia Perlis, 02600, Arau, Perlis (Malaysia)

2017-03-05

Highlights: • Monoazo and diazo dyes were used as electron acceptor in the abiotic cathode of MFC. • Simultaneous decolourisation and bioelectricity generation were achieved. • Azo dye structures influenced the decolourisation performance. • Positive relation between decolourisation rate and power performance. - Abstract: Monoazo and diazo dyes [New coccine (NC), Acid orange 7 (AO7), Reactive red 120 (RR120) and Reactive green 19 (RG19)] were employed as electron acceptors in the abiotic cathode of microbial fuel cell. The electrons and protons generated from microbial organic oxidation at the anode which were utilized for electrochemical azo dye reduction at the cathodic chamber was successfully demonstrated. When NC was employed as the electron acceptor, the chemical oxygen demand (COD) removal and dye decolourisation efficiencies obtained at the anodic and cathodic chamber were 73 ± 3% and 95.1 ± 1.1%, respectively. This study demonstrated that the decolourisation rates of monoazo dyes were ∼50% higher than diazo dyes. The maximum power density in relation to NC decolourisation was 20.64 mW/m{sup 2}, corresponding to current density of 120.24 mA/m{sup 2}. The decolourisation rate and power output of different azo dyes were in the order of NC > AO7 > RR120 > RG19. The findings revealed that the structure of dye influenced the decolourisation and power performance of MFC. Azo dye with electron-withdrawing group at para substituent to azo bond would draw electrons from azo bond; hence the azo dye became more electrophilic and more favourable for dye reduction.

Fundamental Insights into Propionate Oxidation in Microbial Electrolysis Cells Using a Combination of Electrochemical, Molecular biology and Electron Balance Approaches

KAUST Repository

Rao, Hari Ananda

2016-11-01

Increasing demand for freshwater and energy is pushing towards the development of alternative technologies that are sustainable. One of the realistic solutions to address this is utilization of the renewable resources like wastewater. Conventional wastewater treatment processes can be highly energy demanding and can fails to recover the full potential of useful resources such as energy in the wastewater. As a consequence, there is an urgent necessity for sustainable wastewater treatment technologies that could harness such resources present in wastewaters. Advanced treatment process based on microbial electrochemical technologies (METs) such as microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) have a great potential for the resources recovery through a sustainable wastewater treatment process. METs rely on the abilities of microorganisms that are capable of transferring electrons extracellularly by oxidizing the organic matter in the wastewater and producing electrical current for electricity generation (MFC) or H2 and CH4 production (MEC). Propionate is an important volatile fatty acid (VFA) (24-70%) in some wastewaters and accumulation of this VFA can cause a process failure in a conventional anaerobic digestion (AD) system. To address this issue, MECs were explored as a novel, alternative wastewater treatment technology, with a focus on a better understanding of propionate oxidation in the anode of MECs. Having such knowledge could help in the development of more robust and efficient wastewater treatment systems to recover energy and produce high quality effluents. Several studies were conducted to: 1) determine the paths of electron flow in the anode of propionate fed MECs low (4.5 mM) and high (36 mM) propionate concentrations; 2) examine the effect of different set anode potentials on the electrochemical performance, propionate degradation, electron fluxes, and microbial community structure in MECs fed propionate; and 3) examine the temporal

Quorum sensing alters the microbial community of electrode-respiring bacteria and hydrogen scavengers toward improving hydrogen yield in microbial electrolysis cells

International Nuclear Information System (INIS)

Cai, Weiwei; Zhang, Zhaojing; Ren, Ge; Shen, Qiuxuan; Hou, Yanan; Ma, Anzhou; Deng, Ye; Wang, Aijie; Liu, Wenzong

2016-01-01

Highlights: • Enhanced hydrogen yield has been achieved with addition of AHL. • AHL regulated exoelectrogens resulting in electrochemical activity enhancement. • Microbial community shift in cathodic biofilm inhibited hydrogen loss. - Abstract: Quorum sensing has been widely applied to enhance the energy recovery of bioelectrochemical system as a sustainable pathway to enhance communication between cells and electrodes. However, how signalling molecules (acyl-homoserine lactones, AHLs) regulate the microbial community to improve hydrogen generation in microbial electrolysis cells (MECs) is not well understood, especially the subsequent influence on interspecies relationships among not only electrode-respiring bacteria but also hydrogen scavengers. Understanding AHL regulation in a complicated and actual biofilm system will be valuable for future applications of microbial electrochemical technology. Herein, we added short-chain AHLs (3OC6) to regulate the biofilm community on bio-electrodes in MECs. As a result, hydrogen yields were enhanced with AHL addition, increasing by 5.57%, 38.68%, and 81.82% with varied external voltages (0.8 V, 0.6 V, and 0.4 V, respectively). Accordingly, overall reactor performance was enhanced, including coulombic efficiency, electron recovery efficiency, and energy efficiency. Based on an electrochemical impedance spectra analysis, the structured biofilm under simple nutrient conditions (acetate) showed a lower internal resistance with AHL addition, indicating that the microbial communities were altered to enhance electron transfer between the biofilm and electrode. The change in the cathodic microbial structure with more electrochemically active bacteria and fewer hydrogen scavengers could contribute to a higher electron recovery and hydrogen yield with AHL addition. The regulation of the microbial community structure by AHLs represents a potential strategy to enhance electron transfer and hydrogen generation in

Utility of Tissue Transglutaminase Immunohistochemistry in Pediatric Duodenal Biopsies: Patterns of Expression and Role in Celiac Disease—A Clinicopathologic Review

Directory of Open Access Journals (Sweden)

Saeeda Almarzooqi

2013-01-01

Full Text Available Tissue transglutaminase (tTG is a ubiquitous multifunctional protein. It has roles in various cellular processes. tTG is a major target of autoantibodies in celiac disease, and its expression by immunohistochemistry in pediatric celiac disease has not been fully examined. We studied tTG expression in 78 pediatric duodenal biopsies by utilizing an antibody to transglutaminase 2. Serum tTG was positive in all celiac cases evaluated. Serum antiserum endomysial antibody (EMA and tTG were negative in all control subjects and in inflammatory bowel disease and eosinophilic gastroenteritis. There was a statistically significant difference between cases of celiac disease and normal controls in terms of tTG immunohistochemical staining in duodenal biopsies surface epithelium ( value = 0.0012. There was no significant statistical difference in terms of staining of the villous surface or crypt between the cases of celiac disease and cases with IBD ( value = 0.5970 and 0.5227, resp.. There was no detected correlation between serum tTG values and immunohistochemical positivity on duodenal biopsy in cases of celiac disease ( value = 1. There was no relationship between Marsh classification and positivity of villous surface for tTG ( value = 0.4955. We conclude that tTG has limited utility in diagnosis of celiac disease in pediatric duodenal biopsies.

Free-living spirochetes from Cape Cod microbial mats detected by electron microscopy

Science.gov (United States)

Teal, T. H.; Chapman, M.; Guillemette, T.; Margulis, L.

1996-01-01

Spirochetes from microbial mats and anaerobic mud samples collected in salt marshes were studied by light microscopy, whole mount and thin section transmission electron microscopy. Enriched in cellobiose-rifampin medium, selective for Spirochaeta bajacaliforniensis, seven distinguishable spirochete morphotypes were observed. Their diameters ranged from 0.17 micron to > 0.45 micron. Six of these morphotypes came from southwest Cape Cod, Massachusetts: five from Microcoleus-dominated mat samples collected at Sippewissett salt marsh and one from anoxic mud collected at School Street salt marsh (on the east side of Eel Pond). The seventh morphotype was enriched from anoxic mud sampled from the north central Cape Cod, at the Sandy Neck salt marsh. Five of these morphotypes are similar or identical to previously described spirochetes (Leptospira, Spirochaeta halophila, Spirochaeta bajacaliforniensis, Spirosymplokos deltaeiberi and Treponema), whereas the other two have unique features that suggest they have not been previously described. One of the morphotypes resembles Spirosymplokos deltaeiberi (the largest free-living spirochete described), in its large variable diameter (0.4-3.0 microns), cytoplasmic granules, and spherical (round) bodies with composite structure. This resemblance permits its tentative identification as a Sippewissett strain of Spirosymplokos deltaeiberi. Microbial mats samples collected in sterile Petri dishes and stored dry for more than four years yielded many organisms upon rewetting, including small unidentified spirochetes in at least 4 out of 100 enrichments.

Diagnostic accuracy of serum iga anti-tissue transglutaminase antibody in the diagnosis of celiac disease

International Nuclear Information System (INIS)

Lodhi, M. A.; Ayub, A.; Saleem, M. Z.; Munir, T.

2017-01-01

Objective: To determine the diagnostic accuracy of serum IgA anti-tissue transglutaminase antibody in the diagnosis of celiac disease taking histopathology as gold standard. Study Design: Cross-sectional survey. Place and Duration of Study: This study was conducted at the department of Pediatrics, Military Hospital Rawalpindi from April 2015 to July 2016. Patients and Methods: Ninety-five consecutive children presenting with suspicion of celiac disease were included in this study after taking written informed consent. A predesigned proforma was used to record patient’s demographic details. Anti-tTG level of >=25 U/ml was taken as diagnostic of celiac disease while results of histopathology on endoscopic biopsy were taken as gold standard. Results: The mean age of the patients was 6.48 ± 3.20 years and majority (n=53, 55.8 percent) of the children were aged between 5 to 10 years. The serum anti-tTG level ranged from 8.0 U/ml to 759.0 U/ml with a mean of 298.75 ± 225.51 U/ml. Taking a cut-off value of >=25 U/ml for anti-tTG, 81 (85.3 percent) children were suspected of celiac disease. Histopathology of endoscopic biopsy confirmed celiac disease in 68 (71.6 percent) children with 62 true positive, 19 false positive, 6 false negative and 8 true negative cases. It yielded 91.18 percent sensitivity, 29.63 percent specificity and 73.68 percent accuracy for anti-tTG (>=25 U/ml) in the diagnosis of celiac disease with positive and negative predictive values of 76.54 percent and 57.14 percent respectively. Conclusion: IgA anti-tissue transglutaminase antibody (>=25 U/ml) was found to be highly sensitive test for the detection of celiac disease in children. (author)

Effects of gamma and electron beam irradiation on the microbial quality of steamed tofu rolls

International Nuclear Information System (INIS)

Jia, Qian; Gao, Meixu; Li, Shurong; Wang, Zhidong

2013-01-01

The effectiveness of two kinds of radiation processing, gamma and electron beam (ebeam) irradiation, for the inactivation of Staphylococcus aureus, Salmonella enteritidis and Listeria innocua which were inoculated in pre-sterilised steamed tofu rolls was studied. The corresponding effects of both irradiation types on total bacterial counts (TBCs) in commercial steamed tofu rolls available in the market were also examined. The microbiological results demonstrated that gamma irradiation yielded D 10 values of 0.20, 0.24 and 0.22 kGy for S. aureus, S. enteritidis and L. innocua, respectively. The respective D 10 values for ebeam irradiation were 0.31, 0.35 and 0.27 kGy. Gamma and ebeam irradiation yielded D 10 values of 0.48 and 0.43 kGy for total bacterial counts in commercial steamed tofu rolls, respectively. The results suggest that ebeam irradiation has similar effect on decreasing TBCs in steamed tofu rolls, and gamma irradiation is slightly more effective than ebeam irradiation in reducing the populations of pathogenic bacteria. The observed differences in D 10 -values between them might be due to the significant differences in dose rate applied, and radiation processing of soybean products to improve their microbial quality could be available for other sources of protein. - Highlights: ► Our research material is steamed tofu rolls, a kind of soybean products. ► We compared the effects of gamma ray and electron beam irradiation. ► Total bacterial and three strains of pathogens are studied in our research. ► We reported electron beam has similar decontamination effect as gamma ray. ► Radiation processing of soybean products to improve their microbial quality could be available for other sources of protein.

Antibodies against deamidated gliadin peptides identify adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase.

Science.gov (United States)

Dahle, C; Hagman, A; Ignatova, S; Ström, M

2010-07-01

This study was done to evaluate the diagnostic utility of antibodies against deamidated gliadin peptides compared to traditional markers for coeliac disease. To evaluate diagnostic utility of antibodies against deamidated gliadin peptide (DGP). Sera from 176 adults, referred for endoscopy without previous analysis of antibodies against tissue transglutaminase (tTG) or endomysium (EmA), were retrospectively analysed by ELISAs detecting IgA/IgG antibodies against DGP or a mixture of DGP and tTG, and compared with IgA-tTG and EmA. Seventy-nine individuals were diagnosed with coeliac disease. Receiver operating characteristic analyses verified the manufacturers' cut-off limits except for IgA/IgG-DGP/tTG. In sera without IgA deficiency, the sensitivity was higher for IgA/IgG-DGP (0.85-0.87) compared with IgA-tTg (0.76) and EmA (0.61). All tests showed high specificity (0.95-1.00). Eighteen coeliac disease-sera were negative regarding IgA-tTG, nine of which were positive for IgA/IgG-DGP. Sera from coeliac disease-patients >70 years were more often negative for IgA-tTG (50%) and IgA/IgG-DGP (36%) than younger patients (15% and 8% respectively) (P adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase. Serology is often negative in elderly patients with coeliac disease; a small bowel biopsy should therefore be performed generously before coeliac disease is excluded.

Cutaneous expressions of interleukin-6 and neutrophil elastase as well as levels of serum IgA antibodies to gliadin nonapeptides, tissue transglutaminase and epidermal transglutaminase: implications for both autoimmunity and autoinflammation involvement in dermatitis herpetiformis.

Science.gov (United States)

Gornowicz-Porowska, Justyna; Bowszyc-Dmochowska, Monika; Seraszek-Jaros, Agnieszka; Kaczmarek, Elżbieta; Pietkiewicz, Paweł; Dmochowski, Marian

2014-01-01

Dermatitis herpetiformis (DH) seems to be a chronic immune-mediated inflammatory disease of partially known origin. In light of its known biological functions and its involvement in tissue pathology in other disease states, particularly in nickel-induced allergic contact dermatitis coexisting with DH, it would appear that the central and peripheral response by neutrophils and their mediators (e.g. neutrophil elastase - NE) in DH may be partially mediated by interleukin-6 (IL-6). The aim of the study was to assess the role of IL -6 in DH lesions by examining the relationships between IL -6/NE cutaneous expression and levels of serum anti-nonapeptides of gliadin (npG) IgA, anti-tissue transglutaminase (tTG) immunoglobulin A (IgA), anti-epidermal transglutaminase (eTG) IgA in DH. In total, 24 DH patients having IgA cutaneous deposition were studied. Immunohistochemistry on paraffin-embedded sections with quantitative digital morphometry was used to measure the intensity of IL -6 and NE cutaneous expressions. Levels of serum anti-npG IgA, anti-tTG IgA and anti-eTG IgA were evaluated with ELISA. We found no statistically significant correlation between the NE and IL -6 expression intensities. Our results revealed also a lack of correlations between NE/IL -6 expressions and levels of anti-npG IgA, anti-tTG IgA, anti-eTG IgA in DH. However, the IL -6 expression level was significantly lower than that of NE. The lack of correlations suggested no substantial interactions between IL -6, NE, IgA/npG, IgA/tTG or IgA/eTG in DH. Presented results might indicate the heterogenetic nature of DH pathogenesis suggesting further that both autoimmune and autoinflammatory phenomena may be involved in DH cutaneous pathology.

Establishment and metabolic analysis of a model microbial community for understanding trophic and electron accepting interactions of subsurface anaerobic environments

Directory of Open Access Journals (Sweden)

Yang Zamin K

2010-05-01

Full Text Available Abstract Background Communities of microorganisms control the rates of key biogeochemical cycles, and are important for biotechnology, bioremediation, and industrial microbiological processes. For this reason, we constructed a model microbial community comprised of three species dependent on trophic interactions. The three species microbial community was comprised of Clostridium cellulolyticum, Desulfovibrio vulgaris Hildenborough, and Geobacter sulfurreducens and was grown under continuous culture conditions. Cellobiose served as the carbon and energy source for C. cellulolyticum, whereas D. vulgaris and G. sulfurreducens derived carbon and energy from the metabolic products of cellobiose fermentation and were provided with sulfate and fumarate respectively as electron acceptors. Results qPCR monitoring of the culture revealed C. cellulolyticum to be dominant as expected and confirmed the presence of D. vulgaris and G. sulfurreducens. Proposed metabolic modeling of carbon and electron flow of the three-species community indicated that the growth of C. cellulolyticum and D. vulgaris were electron donor limited whereas G. sulfurreducens was electron acceptor limited. Conclusions The results demonstrate that C. cellulolyticum, D. vulgaris, and G. sulfurreducens can be grown in coculture in a continuous culture system in which D. vulgaris and G. sulfurreducens are dependent upon the metabolic byproducts of C. cellulolyticum for nutrients. This represents a step towards developing a tractable model ecosystem comprised of members representing the functional groups of a trophic network.

MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process.

Science.gov (United States)

Araujo, Pablo Granda; Gras, Anna; Ginovart, Marta

2016-01-01

Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs) using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics) can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4 (+), NO3 (-), NO2 (-), N2) to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc). MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

Extracellular enzymes facilitate electron uptake in biocorrosion and bioelectrosynthesis.

Science.gov (United States)

Deutzmann, Jörg S; Sahin, Merve; Spormann, Alfred M

2015-04-21

Direct, mediator-free transfer of electrons between a microbial cell and a solid phase in its surrounding environment has been suggested to be a widespread and ecologically significant process. The high rates of microbial electron uptake observed during microbially influenced corrosion of iron [Fe(0)] and during microbial electrosynthesis have been considered support for a direct electron uptake in these microbial processes. However, the underlying molecular mechanisms of direct electron uptake are unknown. We investigated the electron uptake characteristics of the Fe(0)-corroding and electromethanogenic archaeon Methanococcus maripaludis and discovered that free, surface-associated redox enzymes, such as hydrogenases and presumably formate dehydrogenases, are sufficient to mediate an apparent direct electron uptake. In genetic and biochemical experiments, we showed that these enzymes, which are released from cells during routine culturing, catalyze the formation of H2 or formate when sorbed to an appropriate redox-active surface. These low-molecular-weight products are rapidly consumed by M. maripaludis cells when present, thereby preventing their accumulation to any appreciable or even detectable level. Rates of H2 and formate formation by cell-free spent culture medium were sufficient to explain the observed rates of methane formation from Fe(0) and cathode-derived electrons by wild-type M. maripaludis as well as by a mutant strain carrying deletions in all catabolic hydrogenases. Our data collectively show that cell-derived free enzymes can mimic direct extracellular electron transfer during Fe(0) corrosion and microbial electrosynthesis and may represent an ecologically important but so far overlooked mechanism in biological electron transfer. The intriguing trait of some microbial organisms to engage in direct electron transfer is thought to be widespread in nature. Consequently, direct uptake of electrons into microbial cells from solid surfaces is assumed

Effect of anode polarization on biofilm formation and electron transfer in Shewanella oneidensis/graphite felt microbial fuel cells.

Science.gov (United States)

Pinto, David; Coradin, Thibaud; Laberty-Robert, Christel

2018-04-01

In microbial fuel cells, electricity generation is assumed by bacterial degradation of low-grade organics generating electrons that are transferred to an electrode. The nature and efficiency of the electron transfer from the bacteria to the electrodes are determined by several chemical, physical and biological parameters. Specifically, the application of a specific potential at the bioanode has been shown to stimulate the formation of an electro-active biofilm, but the underlying mechanisms remain poorly understood. In this study, we have investigated the effect of an applied potential on the formation and electroactivity of biofilms established by Shewanella oneidensis bacteria on graphite felt electrodes in single- and double-chamber reactor configurations in oxic conditions. Using amperometry, cyclic voltammetry, and OCP/Power/Polarization curves techniques, we showed that a potential ranging between -0.3V and +0.5V (vs. Ag/AgCl/KCl sat.) and its converse application to a couple of electrodes leads to different electrochemical behaviors, anodic currents and biofilm architectures. For example, when the bacteria were confined in the anodic compartment of a double-chamber cell, a negative applied potential (-0.3V) at the bioanode favors a mediated electron transfer correlated with the progressive formation of a biofilm that fills the felt porosity and bridges the graphite fibers. In contrast, a positive applied potential (+0.3V) at the bioanode stimulates a direct electron transfer resulting in the fast-bacterial colonization of the fibers only. These results provide significant insight for the understanding of the complex bacteria-electrode interactions in microbial fuel cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Transglutaminase-treated conjugation of sodium caseinate and corn fiber gum hydrolysate: Interfacial and dilatational properties.

Science.gov (United States)

Liu, Yan; Selig, Michael J; Yadav, Madhav P; Yin, Lijun; Abbaspourrad, Alireza

2018-05-01

This study compliments previous work where peroxidase was successfully used to crosslink corn fiber gum (CFG) with bovine serum albumin and improve CFG's emulsifying properties. Herein, an alternative type of enzyme, transglutaminase, was used to prepare conjugates of CFG and sodium caseinate. Additionally, the CFG was partially hydrolyzed by sulfuric acid and its crosslinking pattern with caseinate was evaluated. The interfacial crosslinking degree between caseinate and CFG increased after hydrolysis according to high performance size exclusion chromatography. The equilibrium interfacial tension of CFG hydrolysate-caseinate conjugate was lower than that of CFG-caseinate conjugate as the rearrangement rate of the CFG hydrolysate-caseinate conjugate was higher. The dilatational modulus of CFG hydrolysate decreased from that of CFG. Copyright © 2018 Elsevier Ltd. All rights reserved.

The effect of processing parameters on the structure of fermented milk products with transglutaminase addition

Directory of Open Access Journals (Sweden)

Iličić Mirela D.

2013-01-01

Full Text Available This study is concerned with the effect of concentration of transglutaminase (TG, content of milk fat and starter culture type (probiotic and kombucha on the structure of fermented milk products. The application of TG significantly improved textural characteristics of the fermented milk products. The firmness of the samples produced from milk with 0.1g100g-1 and 0.9g100g-1 fat content with probiotic starter were by 33% and 17.6% higher, respectively, compared to the control samples. During ten days of storage, the value of the hysteresis loop area of all samples produced from milk with 0.9g100g-1 fat content with TG addition, decreased by 14%. [Projekat Ministarstva nauke Republike Srbije, br. 46009

MbT-Tool: An open-access tool based on Thermodynamic Electron Equivalents Model to obtain microbial-metabolic reactions to be used in biotechnological process

Directory of Open Access Journals (Sweden)

Pablo Araujo Granda

2016-01-01

Full Text Available Modelling cellular metabolism is a strategic factor in investigating microbial behaviour and interactions, especially for bio-technological processes. A key factor for modelling microbial activity is the calculation of nutrient amounts and products generated as a result of the microbial metabolism. Representing metabolic pathways through balanced reactions is a complex and time-consuming task for biologists, ecologists, modellers and engineers. A new computational tool to represent microbial pathways through microbial metabolic reactions (MMRs using the approach of the Thermodynamic Electron Equivalents Model has been designed and implemented in the open-access framework NetLogo. This computational tool, called MbT-Tool (Metabolism based on Thermodynamics can write MMRs for different microbial functional groups, such as aerobic heterotrophs, nitrifiers, denitrifiers, methanogens, sulphate reducers, sulphide oxidizers and fermenters. The MbT-Tool's code contains eighteen organic and twenty inorganic reduction-half-reactions, four N-sources (NH4+, NO3−, NO2−, N2 to biomass synthesis and twenty-four microbial empirical formulas, one of which can be determined by the user (CnHaObNc. MbT-Tool is an open-source program capable of writing MMRs based on thermodynamic concepts, which are applicable in a wide range of academic research interested in designing, optimizing and modelling microbial activity without any extensive chemical, microbiological and programing experience.

Batteryless, wireless sensor powered by a sediment microbial fuel cell.

Science.gov (United States)

Donovan, Conrad; Dewan, Alim; Heo, Deukhyoun; Beyenal, Haluk

2008-11-15

Sediment microbial fuel cells (SMFCs) are considered to be an alternative renewable power source for remote monitoring. There are two main challenges to using SMFCs as power sources: 1) a SMFC produces a low potential at which most sensor electronics do not operate, and 2) a SMFC cannot provide continuous power, so energy from the SMFC must be stored and then used to repower sensor electronics intermittently. In this study, we developed a SMFC and a power management system (PMS) to power a batteryless, wireless sensor. A SMFC operating with a microbial anode and cathode, located in the Palouse River, Pullman, Washington, U.S.A., was used to demonstrate the utility of the developed system. The designed PMS stored microbial energy and then started powering the wireless sensor when the SMFC potential reached 320 mV. It continued powering until the SMFC potential dropped below 52 mV. The system was repowered when the SMFC potential increased to 320 mV, and this repowering continued as long as microbial reactions continued. We demonstrated that a microbial fuel cell with a microbial anode and cathode can be used as an effective renewable power source for remote monitoring using custom-designed electronics.

Reaction of protein and carbohydrates with EDC for making unique biomaterials

Science.gov (United States)

Prior research from this laboratory has demonstrated the feasibility of using chemical and enzymatic treatments on protein and carbohydrate waste products for the purpose of making fillers to enhance the properties of leather. These treatments (microbial transglutaminase, genipin, and polyphenols i...

Extracellular Electron Uptake: Among Autotrophs and Mediated by Surfaces

DEFF Research Database (Denmark)

Tremblay, Pier-Luc; Angenent, Largus T.; Zhang, Tian

2017-01-01

Autotrophic microbes can acquire electrons from solid donors such as steel, other microbial cells, or electrodes. Based on this feature, bioprocesses are being developed for the microbial electrosynthesis (MES) of useful products from the greenhouse gas CO2. Extracellular electron-transfer mechan......Autotrophic microbes can acquire electrons from solid donors such as steel, other microbial cells, or electrodes. Based on this feature, bioprocesses are being developed for the microbial electrosynthesis (MES) of useful products from the greenhouse gas CO2. Extracellular electron......; or (iii) mediator-generating enzymes detached from cells. This review explores the interactions of autotrophs with solid electron donors and their importance in nature and for biosustainable technologies....

Competitive microbial reduction of perchlorate and nitrate with a cathode directly serving as the electron donor

International Nuclear Information System (INIS)

Xie, Daohai; Yu, Hui; Li, Chenchen; Ren, Yuan; Wei, Chaohai; Feng, Chunhua

2014-01-01

Microbial reduction of perchlorate with an electrode as the electron donor represents an emerging technology for remediation of perchlorate contamination; it is important to know how perchlorate reduction behaves when nitrate, a co-contaminant of perchlorate is present. We reported that electrons derived from the electrode can be directly transferred to the bacteria with perchlorate or nitrate as the sole electron acceptor. The presence of nitrate, even at the 0.07 mM level, can slow reduction of perchlorate (0.70 mM) as a poised potential of -0.50 V (vs. SCE) was applied to the inoculated cathode. Increasing the concentration of nitrate resulted in a noticeable inhibitory effect on perchlorate reduction. When the nitrate concentration was 2.10 mM, reduction of 0.70 mM perchlorate was totally inhibited. Bacterial community analyses based on 16S rDNA gene analysis with denaturing gradient gel electrophoresis (DGGE) revealed that most of the bacteria newly enriched on the nitrate and/or perchlorate biocathodes were the known electrochemically active denitrifiers, which possibly prefer to reduce nitrate over perchlorate. These results show that nitrate is a more favorable electron acceptor than perchlorate in the bioelectrochemical system where the cathode directly serves as the electron donor

Microbial quality evaluation and effective decontamination of nutraceutically valued lotus seeds by electron beams and gamma irradiation

International Nuclear Information System (INIS)

Bhat, Rajeev; Sridhar, K.R.; Karim, A.A.

2010-01-01

Lotus seeds are nutraceutically valued natural plant produce, which succumbs to microbial contamination, predominantly to toxigenic moulds. Results of the present study revealed seed coat portion to harbor higher proportion of microbial load, particularly fungi than cotyledon portion. Among the mycotoxins analyzed, aflatoxins (B 1 , B 2 , G 1 and G 2 ) were below detectable limits, while the seeds were devoid of Ochratoxin-A (OTA). Application of different doses of electron beam and gamma irradiation (0, 2.5, 5, 7.5, 10, 15 and 30 kGy) for decontamination purpose revealed significant dose-dependent decrease in the fungal contaminants (P<0.05). However, the contaminant yeasts could survive up to 10 kGy dose, which could be completely eliminated at 15 kGy. From the results obtained, a dose range between 10 and 15 kGy is recommended for complete decontamination, as these doses have also been shown earlier to have minimal effects on nutritional and functional properties of lotus seeds.

Small molecule inhibitors target the tissue transglutaminase and fibronectin interaction.

Directory of Open Access Journals (Sweden)

Bakhtiyor Yakubov

Full Text Available Tissue transglutaminase (TG2 mediates protein crosslinking through generation of ε-(γ-glutamyl lysine isopeptide bonds and promotes cell adhesion through interaction with fibronectin (FN and integrins. Cell adhesion to the peritoneal matrix regulated by TG2 facilitates ovarian cancer dissemination. Therefore, disruption of the TG2-FN complex by small molecules may inhibit cell adhesion and metastasis. A novel high throughput screening (HTS assay based on AlphaLISA™ technology was developed to measure the formation of a complex between His-TG2 and the biotinylated FN fragment that binds TG2 and to discover small molecules that inhibit this protein-protein interaction. Several hits were identified from 10,000 compounds screened. The top candidates selected based on >70% inhibition of the TG2/FN complex formation were confirmed by using ELISA and bioassays measuring cell adhesion, migration, invasion, and proliferation. In conclusion, the AlphaLISA bead format assay measuring the TG2-FN interaction is robust and suitable for HTS of small molecules. One compound identified from the screen (TG53 potently inhibited ovarian cancer cell adhesion to FN, cell migration, and invasion and could be further developed as a potential inhibitor for ovarian cancer dissemination.

Distribution of transglutaminase family members in mouse whole body sections.

Science.gov (United States)

Tatsukawa, Hideki; Abe, Natsumi; Ohashi, Shintaro; Hitomi, Kiyotaka

2015-11-27

Transglutaminases (TGs) comprise a protein family in which the members catalyze the formation of isopeptide bonds between glutamine and lysine residues in various proteins. Eight enzymes have been identified and designated as factor XIII (FXIII) and TG1-7. Expression studies of four major members, i.e., FXIII, TG1, TG2, and TG3, have been performed in a relatively large number of mammalian tissues in comparison with those on the other isozymes. The structural and biochemical characteristics of these individual isozymes and expression analyses of TG family in some tissue extracts have been reported, but there have been no simultaneous comparative analyses of both their mRNA and protein expression patterns in tissues distributions. Thus, we developed novel experimental systems for in situ hybridization using cryofilm attached to whole body sections of neonatal mice, thereby obtaining data regarding the tissue distributions of the major TG isozymes. In this study, we performed the first detailed comparative analysis of the mRNA and protein distribution studies of TG family members in a wide range of mouse tissues. These data will be helpful for elucidating the unknown physiological and pathological functions of TGs. Copyright © 2015 Elsevier Inc. All rights reserved.

Studies about behavior of microbial degradation of organic compounds

International Nuclear Information System (INIS)

Ohtsuka, Makiko

2003-02-01

Some of TRU waste include organic compounds, thus these organic compounds might be nutrients for microbial growth at disposal site. This disposal system might be exposed to high alkali condition by cement compounds as engineering barrier material. In the former experimental studies, it has been supposed that microbial exist under pH = 12 and the microbial activity acclimated to high alkali condition are able to degrade asphalt under anaerobic condition. Microbes are called extremophile that exist in cruel habitat as high alkali or reductive condition. We know less information about the activity of extremophile, though any recent studies reveal them. In this study, the first investigation is metabolic pathway as microbial activity, the second is microbial degradation of aromatic compounds in anaerobic condition, and the third is microbial activity under high alkali. Microbial metabolic pathway consist of two systems that fulfill their function each other. One system is to generate energy for microbial activities and the other is to convert substances for syntheses of organisms' structure materials. As these systems are based on redox reaction between substances, it is made chart of the microbial activity region using pH, Eh, and depth as parameter, There is much report that microbe is able to degrade aromatic compounds under aerobic or molecular O 2 utilizing condition. For degradation of aromatic compounds in anaerobic condition, supplying electron acceptor is required. Co-metabolism and microbial consortia has important role, too. Alcalophile has individual transporting system depending Na + and acidic compounds contained in cell wall. Generating energy is key for survival and growth under high alkali condition. Co-metabolism and microbial consortia are effective for microbial degradation of aromatic compounds under high alkali and reductive condition, and utilizable electron acceptor and degradable organic compounds are required for keeping microbial activity and

A rare case of Addison's disease, hepatitis, thyreoiditis, positive IgG anti-tissue transglutaminase antibodies and partial IgA deficiency.

Science.gov (United States)

Baleva, Marta P; Mihaylova, Snejina; Yankova, Petja; Atanasova, Iliana; Nikolova-Vlahova, Milena; Naumova, Elissaveta

2016-01-01

Selective IgA deficiency (IgAD) is the most prevalent type of primary immune deficiencies, but partial IgA deficiency is even more common. Addison's disease is a rare condition associated with primary adrenal insufficiency due to infection or autoimmune destruction of the adrenals. The association between IgA deficiency and Addison's disease is very rare. We observed a 22-year-old male patient with marked darkening of the skin, especially on the palms and areolae, jaundice on the skin and sclera, astheno-adynamia, hypotension (80/50 mm Hg), and pain in the right hypochondrium. The laboratory investigations revealed increased serum levels of total and indirect bilirubin, AST, ALT, GGT and LDH, negative HBsAg, anti-HBc IgM, anti-HCV and anti-HAV IgM, very low serum IgA levels (0.16 g/l) with normal IgG and IgM, negative ANA, ANCA, AMA, LKM-1, anti-GAD-60, anti-IA-2, anti-thyroglobulin antibodies, a mild increase in anti-TPO antibodies titer, a marked increase in IgG anti-tissue transglutaminase antibodies, with no typical changes in cellular immunity, negative T-SPOT-TB test, HLA - A*01; B*08; DRB1*03; DQB1*02, karyotype - 46, XY. We present a rare case of partial IgA deficiency with Addison's disease, hepatitis, thyroiditis and positive anti-tissue transglutaminase antibodies. IgAD and some autoimmune disorders share several predisposing HLA genes, thus explaining the increased prevalence of IgAD in certain patient groups.

Identification of a preferred substrate peptide for transglutaminase 3 and detection of in situ activity in skin and hair follicles.

Science.gov (United States)

Yamane, Asaka; Fukui, Mina; Sugimura, Yoshiaki; Itoh, Miho; Alea, Mileidys Perez; Thomas, Vincent; El Alaoui, Said; Akiyama, Masashi; Hitomi, Kiyotaka

2010-09-01

Transglutaminases (TGases) are a family of enzymes that catalyze cross-linking reactions between proteins. During epidermal differentiation, these enzymatic reactions are essential for formation of the cornified envelope, which consists of cross-linked structural proteins. Two main transglutaminases isoforms, epidermal-type (TGase 3) and keratinocyte-type (TGase 1), are cooperatively involved in this process of differentiating keratinocytes. Information regarding their substrate preference is of great importance to determine the functional role of these isozymes and clarify their possible co-operative action. Thus far, we have identified highly reactive peptide sequences specifically recognized by TGases isozymes such as TGase 1, TGase 2 (tissue-type isozyme) and the blood coagulation isozyme, Factor XIII. In this study, several substrate peptide sequences for human TGase 3 were screened from a phage-displayed peptide library. The preferred substrate sequences for TGase 3 were selected and evaluated as fusion proteins with mutated glutathione S-transferase. From these studies, a highly reactive and isozyme-specific sequence (E51) was identified. Furthermore, this sequence was found to be a prominent substrate in the peptide form and was suitable for detection of in situ TGase 3 activity in the mouse epidermis. TGase 3 enzymatic activity was detected in the layers of differentiating keratinocytes and hair follicles with patterns distinct from those of TGase 1. Our findings provide new information on the specific distribution of TGase 3 and constitute a useful tool to clarify its functional role in the epidermis.

Utilization of subsurface microbial electrochemical systems to elucidate the mechanisms of competition between methanogenesis and microbial iron(III)/humic acid reduction in Arctic peat soils

Science.gov (United States)

Friedman, E. S.; Miller, K.; Lipson, D.; Angenent, L. T.

2012-12-01

High-latitude peat soils are a major carbon reservoir, and there is growing concern that previously dormant carbon from this reservoir could be released to the atmosphere as a result of continued climate change. Microbial processes, such as methanogenesis and carbon dioxide production via iron(III) or humic acid reduction, are at the heart of the carbon cycle in Arctic peat soils [1]. A deeper understanding of the factors governing microbial dominance in these soils is crucial for predicting the effects of continued climate change. In previous years, we have demonstrated the viability of a potentiostatically-controlled subsurface microbial electrochemical system-based biosensor that measures microbial respiration via exocellular electron transfer [2]. This system utilizes a graphite working electrode poised at 0.1 V NHE to mimic ferric iron and humic acid compounds. Microbes that would normally utilize these compounds as electron acceptors donate electrons to the electrode instead. The resulting current is a measure of microbial respiration with the electrode and is recorded with respect to time. Here, we examine the mechanistic relationship between methanogenesis and iron(III)- or humic acid-reduction by using these same microbial-three electrode systems to provide an inexhaustible source of alternate electron acceptor to microbes in these soils. Chamber-based carbon dioxide and methane fluxes were measured from soil collars with and without microbial three-electrode systems over a period of four weeks. In addition, in some collars we simulated increased fermentation by applying acetate treatments to understand possible effects of continued climate change on microbial processes in these carbon-rich soils. The results from this work aim to increase our fundamental understanding of competition between electron acceptors, and will provide valuable data for climate modeling scenarios. 1. Lipson, D.A., et al., Reduction of iron (III) and humic substances plays a major

Production of Transglutaminase by Streptoverticillium ladakanum NRRL-3191 Using Glycerol as Carbon Source

Directory of Open Access Journals (Sweden)

Simón J. Téllez-Luis

2004-01-01

Full Text Available The enzyme transglutaminase (TG catalyses the formation of covalent bonds between adjacent proteins, thereby improving the gel structure of proteins and has important applications for the food industry. The aims of this work were: (i to elucidate the effect of agitation speed during the biotechnological production of TG by Streptoverticillium ladakanum NRRL-3191 using glycerol as carbon source; and (ii to improve TG production by optimising the composition of media based on glycerol, xylose and casein. An agitation speed of 250 rpm and a fermentation time of 72 h resulted in the optimal enzymatic activity (0.628 U/mL with a productivity of 0.087 U/(mL·h. The composition of media with glycerol, xylose and casein were optimised using an experimental design to improve TG production. The model predicts that the maximum TG activity (0.725 U/mL can be obtained using glycerol 50.5 g/L and casein 20 g/L without the addition of xylose.

Effect of transglutaminase on some properties of cake enriched with various protein sources.

Science.gov (United States)

Alp, H; Bilgiçli, N

2008-06-01

The effect of transglutaminase (TG) enzyme addition (0% and 0.09%) on batter and cake properties, prepared with different protein sources (nonfat dry milk [NFDM], soy flour, and soymilk) and flour types (type A with 11.4% protein and type B with 8.6% protein), was investigated. Specific gravity and pH of cake batters were determined, and physical and chemical analysis of the cake samples was performed. Soy products improved cake weight, volume, softness, protein, and fat contents. NFDM increased the crust redness and crumb lightness more than the other protein sources. TG enzyme addition affected the volume, softness, crust, and crumb color of the cake samples significantly (P flour B with lower protein gave more puffed, symmetrical, and softer cake samples. TG had a potential application with different protein sources in cake production. Especially interactions between TG with soy flour and TG and wheat flour with high protein content were important in cake formulations due to the softening effect on crumb.

Diversity and function of the microbial community on anodes of sediment microbial fuel cells fueled by root exudates

Energy Technology Data Exchange (ETDEWEB)

Cabezas da Rosa, Angela

2010-11-26

Anode microbial communities are essential for current production in microbial fuel cells. Anode reducing bacteria are capable of using the anode as final electron acceptor in their respiratory chain. The electrons delivered to the anode travel through a circuit to the cathode where they reduce oxygen to water generating an electric current. A novel type of sediment microbial fuel cell (SMFC) harvest energy from photosynthetically derived compounds released through the roots. Nothing is known about anode microbial communities of this type of microbial fuel cell. This work consists of three parts. The first part focuses on the study of bacterial and archaeal community compositions on anodes of SMFCs fueled by rice root exudates. By using terminal restriction fragment length polymorphism (T-RFLP), a profiling technique, and cloning / sequencing of 16S rRNA, we determined that the support type used for the plant (vermiculite, potting soil or rice field soil) is an important factor determining the composition of the microbial community. Finally, by comparing microbial communities of current producing anodes and non-current producing controls we determined that Desulfobulbus- and Geobacter-related populations were probably most important for current production in potting soil and rice field soil SMFCs, respectively. However, {delta}-proteobacterial Anaeromyxobacter spp., unclassified {delta}-proteobacteria and Anaerolineae were also part of the anode biofilm in rice field soil SMFCs and these populations might also play a role in current production. Moreover, distinct clusters of Geobacter and Anaeromyxobacter populations were stimulated by rice root exudates. Regarding Archaea, uncultured Euryarchaea were abundant on anodes of potting soil SMFCs indicating a potential role in current production. In both, rice field soil and potting soil SMFCs, a decrease of Methanosaeta, an acetotrophic methanogen, was detected on current producing anodes. In the second part we focused

INCREASED TISSUE TRANSGLUTAMINASE LEVELS ARE ASSOCIATED WITH INCREASED EPILEPTIFORM ACTIVITY IN ELECTROENCEPHALOGRAPHY AMONG PATIENTS WITH CELIAC DISEASE

Directory of Open Access Journals (Sweden)

Sedat IŞIKAY

2015-12-01

Full Text Available Background - Celiac disease is an autoimmune systemic disorder in genetically predisposed individuals precipitated by gluten ingestion. Objective - In this study, we aimed to determine asymptomatic spike-and-wave findings on electroencephalography in children with celiac disease. Methods - A total of 175 children with the diagnosis of celiac disease (study group and 99 age- and sex-matched healthy children as controls (control group were included in the study. In order to determine the effects of gluten free diet on laboratory and electroencephalography findings, the celiac group is further subdivided into two as newly-diagnosed and formerly-diagnosed patients. Medical histories of all children and laboratory findings were all recorded and neurologic statuses were evaluated. All patients underwent a sleep and awake electroencephalography. Results - Among 175 celiac disease patients included in the study, 43 were newly diagnosed while 132 were formerly-diagnosed patients. In electroencephalography evaluation of patients the epileptiform activity was determined in 4 (9.3% of newly diagnosed and in 2 (1.5% of formerly diagnosed patients; on the other hand the epileptiform activity was present in only 1 (1.0% of control cases. There was a statistically significant difference between groups in regards to the presence of epileptiform activity in electroencephalography. Pearson correlation analysis revealed that epileptiform activity in both sleep and awake electroencephalography were positively correlated with tissue transglutaminase levels (P=0.014 and P=0.019, respectively. Conclusion - We have determined an increased epileptiform activity frequency among newly-diagnosed celiac disease patients compared with formerly-diagnosed celiac disease patients and control cases. Moreover the tissue transglutaminase levels were also correlated with the presence of epileptiform activity in electroencephalography. Among newly diagnosed celiac disease patients

Inhibition of transglutaminase 2 reduces efferocytosis in human macrophages: Role of CD14 and SR-AI receptors.

Science.gov (United States)

Eligini, S; Fiorelli, S; Tremoli, E; Colli, S

2016-10-01

Transglutaminase 2 (TGM2), a member of the transglutaminase family of enzymes, is a multifunctional protein involved in numerous events spanning from cell differentiation, to signal transduction, apoptosis, and wound healing. It is expressed in a variety of cells, macrophages included. Macrophage TGM2 promotes the clearance of apoptotic cells (efferocytosis) and emerging evidence suggests that defective efferocytosis contributes to the consequences of inflammation-associated diseases, including atherosclerotic lesion progression and its sequelae. Of interest, active TGM2 identified in human atherosclerotic lesions plays critical roles in plaque stability through effects on matrix cross-linking and TGFβ activity. This study explores the mechanisms by which TGM2 controls efferocytosis in human macrophages. Herein we show that TGM2 increases progressively during monocyte differentiation towards macrophages and controls their efferocytic potential as well as morphology and viability. Two experimental approaches that took advantage of the inhibition of TGM2 activity and protein silencing give proof that TGM2 reduction significantly impairs macrophage efferocytosis. Among the mechanisms involved we highlighted a role of the receptors CD14 and SR-AI whose levels were markedly reduced by TGM2 inhibition. Conversely, CD36 receptor and αvβ3 integrin levels were not influenced. Of note, lipid accumulation and IL-10 secretion were reduced in macrophages displaying defective efferocytosis. Overall, our data define a crucial role of TGM2 activity during macrophage differentiation via mechanisms involving CD14 and SR-AI receptors and show that TGM2 inhibition triggers a pro-inflammatory phenotype. Copyright © 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

A Homozygous Missense Mutation in TGM5 Abolishes Epidermal Transglutaminase 5 Activity and Causes Acral Peeling Skin Syndrome

Science.gov (United States)

Cassidy, Andrew J.; van Steensel, Maurice A. M.; Steijlen, Peter M.; van Geel, Michel; Velden, Jaap van der; Morley, Susan M.; Terrinoni, Alessandro; Melino, Gerry; Candi, Eleonora; McLean, W. H. Irwin

2005-01-01

Peeling skin syndrome is an autosomal recessive genodermatosis characterized by the shedding of the outer epidermis. In the acral form, the dorsa of the hands and feet are predominantly affected. Ultrastructural analysis has revealed tissue separation at the junction between the granular cells and the stratum corneum in the outer epidermis. Genomewide linkage analysis in a consanguineous Dutch kindred mapped the gene to 15q15.2 in the interval between markers D15S1040 and D15S1016. Two homozygous missense mutations, T109M and G113C, were found in TGM5, which encodes transglutaminase 5 (TG5), in all affected persons in two unrelated families. The mutation was present on the same haplotype in both kindreds, indicating a probable ancestral mutation. TG5 is strongly expressed in the epidermal granular cells, where it cross-links a variety of structural proteins in the terminal differentiation of the epidermis to form the cornified cell envelope. An established, in vitro, biochemical cross-linking assay revealed that, although T109M is not pathogenic, G113C completely abolishes TG5 activity. Three-dimensional modeling of TG5 showed that G113C lies close to the catalytic domain, and, furthermore, that this glycine residue is conserved in all known transglutaminases, which is consistent with pathogenicity. Other families with more-widespread peeling skin phenotypes lacked TGM5 mutations. This study identifies the first causative gene in this heterogeneous group of skin disorders and demonstrates that the protein cross-linking function performed by TG5 is vital for maintaining cell-cell adhesion between the outermost layers of the epidermis. PMID:16380904

Microbial ecology to manage processes in environmental biotechnology.

Science.gov (United States)

Rittmann, Bruce E

2006-06-01

Microbial ecology and environmental biotechnology are inherently tied to each other. The concepts and tools of microbial ecology are the basis for managing processes in environmental biotechnology; and these processes provide interesting ecosystems to advance the concepts and tools of microbial ecology. Revolutionary advancements in molecular tools to understand the structure and function of microbial communities are bolstering the power of microbial ecology. A push from advances in modern materials along with a pull from a societal need to become more sustainable is enabling environmental biotechnology to create novel processes. How do these two fields work together? Five principles illuminate the way: (i) aim for big benefits; (ii) develop and apply more powerful tools to understand microbial communities; (iii) follow the electrons; (iv) retain slow-growing biomass; and (v) integrate, integrate, integrate.

Antitissue Transglutaminase Normalization Postdiagnosis in Children With Celiac Disease.

Science.gov (United States)

Isaac, Daniela Migliarese; Rajani, Seema; Yaskina, Maryna; Huynh, Hien Q; Turner, Justine M

2017-08-01

Limited pediatric data exist examining the trend and predictors of antitissue transglutaminase (atTG) normalization over time in children with celiac disease (CD). We aimed to evaluate time to normalization of atTG in children after CD diagnosis, and to assess for independent predictors affecting this duration. A retrospective chart review was completed in pediatric patients with CD diagnosed from 2007 to 2014 at the Stollery Children's Hospital Celiac Clinic (Edmonton, Alberta, Canada). The clinical predictors assessed for impact on time to atTG normalization were initial atTG, Marsh score at diagnosis, gluten-free diet compliance (GFDC), age at diagnosis, sex, ethnicity, medical comorbidities, and family history of CD. Kaplan-Meier survival analysis was completed to assess time to atTG normalization, and Cox regression to assess for independent predictors of this time. A total of 487 patients met inclusion criteria. Approximately 80.5% of patients normalized atTG levels. Median normalization time was 407 days for all patients (95% confidence interval [CI: 361-453]), and 364 days for gluten-free diet compliant patients (95% CI [335-393]). Type 1 diabetes mellitus (T1DM) patients took significantly longer to normalize at 1204 days (95% CI [199-2209], P normalization time. GFDC was a significant predictor of earlier normalization (OR = 13.91 [7.86-24.62], P normalization. Patients with T1DM are less likely to normalize atTG levels, with longer normalization time. Additional research and education for higher-risk populations are needed.

Impact of the electron donor on in situ microbial nitrate reduction in Opalinus Clay: results from the Mont Terri rock laboratory (Switzerland)

Energy Technology Data Exchange (ETDEWEB)

Bleyen, N.; Smets, S. [Belgian Nuclear Research Centre SCK-CEN, Mol (Belgium); Small, J. [National Nuclear Laboratory NLL, Warrington (United Kingdom); and others

2017-04-15

At the Mont Terri rock laboratory (Switzerland), an in situ experiment is being carried out to examine the fate of nitrate leaching from nitrate-containing bituminized radioactive waste, in a clay host rock for geological disposal. Such a release of nitrate may cause a geochemical perturbation of the clay, possibly affecting some of the favorable characteristics of the host rock. In this in situ experiment, combined transport and reactivity of nitrate is studied inside anoxic and water-saturated chambers in a borehole in the Opalinus Clay. Continuous circulation of the solution from the borehole to the surface equipment allows a regular sampling and online monitoring of its chemical composition. In this paper, in situ microbial nitrate reduction in the Opalinus Clay is discussed, in the presence or absence of additional electron donors relevant for the disposal concept and likely to be released from nitrate-containing bituminized radioactive waste: acetate (simulating bitumen degradation products) and H{sub 2} (originating from radiolysis and corrosion in the repository). The results of these tests indicate that - in case microorganisms would be active in the repository or the surrounding clay - microbial nitrate reduction can occur using electron donors naturally present in the clay (e.g. pyrite, dissolved organic matter). Nevertheless, non-reactive transport of nitrate in the clay is expected to be the main process. In contrast, when easily oxidizable electron donors would be available (e.g. acetate and H{sub 2}), the microbial activity will be strongly stimulated. Both in the presence of H{sub 2} and acetate, nitrite and nitrogenous gases are predominantly produced, although some ammonium can also be formed when H{sub 2} is present. The reduction of nitrate in the clay could have an impact on the redox conditions in the pore-water and might also lead to a gas-related perturbation of the host rock, depending on the electron donor used during denitrification

Microbial Energy Conversion

Energy Technology Data Exchange (ETDEWEB)

Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

2006-10-01

natural gas from the subsurface. The participants discussed--key microbial conversion paths; overarching research issues; current funding models and microbial energy research; education, training, interdisciplinary cooperation and communication. Their recommendations are--Cellulose and lignocellulose are the preferred substrates for producing liquid transportation fuels, of which ethanol is the most commonly considered example. Generating fuels from these materials is still difficult and costly. A number of challenges need to be met in order to make the conversion of cellulose and lignocellulose to transportation fuels more cost-competitive. The design of hydrogen-producing bioreactors must be improved in order to more effectively manage hydrogen removal, oxygen exclusion, and, in the case of photobioreactors, to capture light energy more efficiently. Methane production may be optimized by fine-tuning methanogenic microbial communities. The ability to transfer electrons to an anode in a microbial fuel cell is probably very broadly distributed in the bacterial world. The scientific community needs a larger inventory of cultivated microorganisms from which to draw for energy conversion development. New and unusual organisms for manufacturing fuels and for use in fuel cells can be discovered using bioprospecting techniques. Particular emphasis should be placed on finding microbes, microbial communities, and enzymes that can enhance the conversion of lignocellulosic biomass to usable sugars. Many of the microbial processes critical to energy conversion are carried out by complex communities of organisms, and there is a need to better understand the community interactions that make these transformations possible. Better understanding of microbial community structure, robustness, networks, homeostasis, and cell-to-cell signaling is also needed. A better understanding of the basic enzymology of microorganisms is needed in order to move forward more quickly with microbial energy

Activity-regulating structural changes and autoantibody epitopes in transglutaminase 2 assessed by hydrogen/deuterium exchange

DEFF Research Database (Denmark)

Iversen, Rasmus; Mysling, Simon; Hnida, Kathrin

2014-01-01

The multifunctional enzyme transglutaminase 2 (TG2) is the target of autoantibodies in the gluten-sensitive enteropathy celiac disease. In addition, the enzyme is responsible for deamidation of gluten peptides, which are subsequently targeted by T cells. To understand the regulation of TG2 activity...... and the enzyme's role as an autoantigen in celiac disease, we have addressed structural properties of TG2 in solution by using hydrogen/deuterium exchange monitored by mass spectrometry. We demonstrate that Ca(2+) binding, which is necessary for TG2 activity, induces structural changes in the catalytic core...... domain of the enzyme. Cysteine oxidation was found to abolish these changes, suggesting a mechanism whereby disulfide bond formation inactivates the enzyme. Further, by using TG2-specific human monoclonal antibodies generated from intestinal plasma cells of celiac disease patients, we observed...

Glucose homeostasis in mice is transglutaminase 2 independent.

Directory of Open Access Journals (Sweden)

Siiri E Iismaa

Full Text Available Transglutaminase type 2 (TG2 has been reported to be a candidate gene for maturity onset diabetes of the young (MODY because three different mutations that impair TG2 transamidase activity have been found in 3 families with MODY. TG2 null (TG2(-/- mice have been reported to be glucose intolerant and have impaired glucose-stimulated insulin secretion (GSIS. Here we rigorously evaluated the role of TG2 in glucose metabolism using independently generated murine models of genetic TG2 disruption, which show no compensatory enhanced expression of other TGs in pancreatic islets or other tissues. First, we subjected chow- or fat-fed congenic SV129 or C57BL/6 wild type (WT and TG2(-/- littermates, to oral glucose gavage. Blood glucose and serum insulin levels were similar for both genotypes. Pancreatic islets isolated from these animals and analysed in vitro for GSIS and cholinergic potentiation of GSIS, showed no significant difference between genotypes. Results from intraperitoneal glucose tolerance tests (GTTs and insulin tolerance tests (ITTs were similar for both genotypes. Second, we directly investigated the role of TG2 transamidase activity in insulin secretion using a coisogenic model that expresses a mutant form of TG2 (TG2(R579A, which is constitutively active for transamidase activity. Intraperitoneal GTTs and ITTs revealed no significant differences between WT and TG2(R579A/R579A mice. Given that neither deletion nor constitutive activation of TG2 transamidase activity altered basal responses, or responses to a glucose or insulin challenge, our data indicate that glucose homeostasis in mice is TG2 independent, and question a link between TG2 and diabetes.

Interconnection of Key Microbial Functional Genes for Enhanced Benzo[a]pyrene Biodegradation in Sediments by Microbial Electrochemistry.

Science.gov (United States)

Yan, Zaisheng; He, Yuhong; Cai, Haiyuan; Van Nostrand, Joy D; He, Zhili; Zhou, Jizhong; Krumholz, Lee R; Jiang, He-Long

2017-08-01

Sediment microbial fuel cells (SMFCs) can stimulate the degradation of polycyclic aromatic hydrocarbons in sediments, but the mechanism of this process is poorly understood at the microbial functional gene level. Here, the use of SMFC resulted in 92% benzo[a]pyrene (BaP) removal over 970 days relative to 54% in the controls. Sediment functions, microbial community structure, and network interactions were dramatically altered by the SMFC employment. Functional gene analysis showed that c-type cytochrome genes for electron transfer, aromatic degradation genes, and extracellular ligninolytic enzymes involved in lignin degradation were significantly enriched in bulk sediments during SMFC operation. Correspondingly, chemical analysis of the system showed that these genetic changes resulted in increases in the levels of easily oxidizable organic carbon and humic acids which may have resulted in increased BaP bioavailability and increased degradation rates. Tracking microbial functional genes and corresponding organic matter responses should aid mechanistic understanding of BaP enhanced biodegradation by microbial electrochemistry and development of sustainable bioremediation strategies.

Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

International Nuclear Information System (INIS)

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.; Wang, Zheming

2007-01-01

The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH · 1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reduction of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity

Enabling fast electron transfer through both bacterial outer-membrane redox centers and endogenous electron mediators by polyaniline hybridized large-mesoporous carbon anode for high-performance microbial fuel cells

International Nuclear Information System (INIS)

Zou, Long; Qiao, Yan; Zhong, Canyu; Li, Chang Ming

2017-01-01

Both physical structure and chemical property of an electrode play critical roles in extracellular electron transfer from microbes to electrodes in microbial fuel cells (MFCs). Herein a novel polyaniline hybridized large mesoporous carbon (PANI-LMC) anode is fabricated from natural biomass by nanostructured CaCO 3 template-assisted carbonization followed by in situ chemical polymerizing PANI to enable fast extracellular electron transfer, in which the LMC with rich disorder-interconnected large mesopores (∼20−50 nm) and large surface area facilitates a fast mediated electron transfer through electron mediators, while the decorated PANI on LMC surface enables the direct electron transfer via bacterial outer-membrane redox centers. Owing to the unique synergistic effect from both excellent electron transfer paths, the PANI-LMC hybrid anode harvests high power electricity with a maximum output power density of 1280 mW m −2 in Shewanella putrefaciens CN32 MFCs, 10-fold higher than that of conventional carbon cloth. The findings from this work suggest a new insight on design of high-efficient anode according to the multiple and flexible electrochemical process for practical MFC applications.

Cheese whey protein recovery by ultrafiltration through transglutaminase (TG) catalysis whey protein cross-linking.

Science.gov (United States)

Wen-Qiong, Wang; Lan-Wei, Zhang; Xue, Han; Yi, Lu

2017-01-15

In whey ultrafiltration (UF) production, two main problems are whey protein recovery and membrane fouling. In this study, membrane coupling protein transglutaminase (TG) catalysis protein cross-linking was investigated under different conditions to find out the best treatment. We found that the optimal conditions for protein recovery involved catalyzing whey protein cross-linking with TG (40U/g whey proteins) at 40°C for 60min at pH 5.0. Under these conditions, the recovery rate was increased 15-20%, lactose rejection rate was decreased by 10%, and relative permeate flux was increase 30-40% compared to the sample without enzyme treatment (control). It was noticeable that the total resistance and cake resistance were decreased after enzyme catalysis. This was mainly due to the increased particle size and decreased zeta potential. Therefore, membrane coupling enzyme catalysis protein cross-linking is a potential means for further use. Copyright © 2016. Published by Elsevier Ltd.

Ecological effects of soil properties and metal concentrations on the composition and diversity of microbial communities associated with land use patterns in an electronic waste recycling region.

Science.gov (United States)

Wu, Wencheng; Dong, Changxun; Wu, Jiahui; Liu, Xiaowen; Wu, Yingxin; Chen, Xianbin; Yu, Shixiao

2017-12-01

Soil microbes play vital roles in ecosystem functions, and soil microbial communities may be strongly structured by land use patterns associated with electronic waste (e-waste) recycling activities, which can increase the heavy metal concentration in soils. In this study, a suite of soils from five land use types (paddy field, vegetable field, dry field, forest field, and e-waste recycling site) were collected in Longtang Town, Guangdong Province, South China. Soil physicochemical properties and heavy metal concentrations were measured, and the indigenous microbial assemblages were profiled using 16S rRNA high-throughput sequencing and clone library analyses. The results showed that mercury concentration was positively correlated with both Faith's PD and Chao1 estimates, suggesting that the soil microbial alpha diversity was predominantly regulated by mercury. In addition, redundancy analysis indicated that available phosphorus, soil moisture, and mercury were the three major drivers affecting the microbial assemblages. Overall, the microbial composition was determined primarily by land use patterns, and this study provides a novel insight on the composition and diversity of microbial communities in soils associated with e-waste recycling activities. Copyright © 2017 Elsevier B.V. All rights reserved.

Bentonite. Geotechnical barrier and source for microbial life

International Nuclear Information System (INIS)

Matschiavelli, Nicole; Kluge, Sindy; Cherkouk, Andrea; Steglich, Jennifer

2017-01-01

Due to their properties, namely a high swelling capacity and a low hydraulic conductivity, Bentonites fulfil as geotechnical barrier a sealing and buffering function in the nuclear waste repository. Depending on the mineral composition Bentonites contain many suitable electron-donors and -acceptors, enabling potential microbial life. For the potential repository of highly radioactive waste the microbial mediated transformation of Bentonite could influence its properties as a barrier material. Microcosms were set up containing Bentonite and anaerobic synthetic Opalinus-clay-pore water solution under an N_2/CO_2-atmosphere to elucidate the microbial potential within selected Bentonites. Substrates like acetate and lactate were supplemented to stimulate potential microbial activity. First results show that bentonites represent a source for microbial life, demonstrated by the consumption of lactate and the formation of pyruvate. Furthermore, microbial iron-reduction was determined, which plays a crucial role in Betonite-transformation.

Bentonite. Geotechnical barrier and source for microbial life

Energy Technology Data Exchange (ETDEWEB)

Matschiavelli, Nicole; Kluge, Sindy; Cherkouk, Andrea [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). HZDR Young Investigator Group; Steglich, Jennifer

2017-06-01

Due to their properties, namely a high swelling capacity and a low hydraulic conductivity, Bentonites fulfil as geotechnical barrier a sealing and buffering function in the nuclear waste repository. Depending on the mineral composition Bentonites contain many suitable electron-donors and -acceptors, enabling potential microbial life. For the potential repository of highly radioactive waste the microbial mediated transformation of Bentonite could influence its properties as a barrier material. Microcosms were set up containing Bentonite and anaerobic synthetic Opalinus-clay-pore water solution under an N{sub 2}/CO{sub 2}-atmosphere to elucidate the microbial potential within selected Bentonites. Substrates like acetate and lactate were supplemented to stimulate potential microbial activity. First results show that bentonites represent a source for microbial life, demonstrated by the consumption of lactate and the formation of pyruvate. Furthermore, microbial iron-reduction was determined, which plays a crucial role in Betonite-transformation.

Influence of Porcine Intervertebral Disc Matrix on Stem Cell Differentiation

Directory of Open Access Journals (Sweden)

Hans-Lothar Fuchsbauer

2011-08-01

Full Text Available For back disorders, cell therapy is one approach for a real regeneration of a degenerated nucleus pulposus. Human mesenchymal stem cells (hMSC could be differentiated into nucleus pulposus (NP-like cells and used for cell therapy. Therefore it is necessary to find a suitable biocompatible matrix, which supports differentiation. It could be shown that a differentiation of hMSC in a microbial transglutaminase cross-linked gelatin matrix is possible, but resulted in a more chondrocyte-like cell type. The addition of porcine NP extract to the gelatin matrix caused a differentiation closer to the desired NP cell phenotype. This concludes that a hydrogel containing NP extract without any other supplements could be suitable for differentiation of hMSCs into NP cells. The NP extract itself can be cross-linked by transglutaminase to build a hydrogel free of NP atypical substrates. As shown by side-specific biotinylation, the NP extract contains molecules with free glutamine and lysine residues available for the transglutaminase.

Treatment of foods with 'soft-electrons' (low-energy electrons)

International Nuclear Information System (INIS)

Hayashi, Toru; Todoriki, Setsuko

2003-01-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

Endostatin and transglutaminase 2 are involved in fibrosis of the aging kidney

Science.gov (United States)

Lin, Chi Hua Sarah; Chen, Jun; Zhang, Zhongtao; Johnson, Gail; Cooper, Arthur JL; Feola, Julianne; Bank, Alexander; Shein, Jonathan; Ruotsalainen, Heli; Pihlajaniemi, Taina; Goligorsky, Michael S

2016-01-01

Endostatin (EST), an anti-angiogenic factor, is enriched in aging kidneys. EST is also an interactive partner of transglutaminase 2 (TG2), an enzyme that cross-links extracellular matrix proteins. Here we tested whether EST and TG2 play a role in the fibrosis of aging. In wild type mice, aging kidneys exhibited a 2–4 fold increase in TG2 paralleled by increased cross-linked extracellular matrix proteins and fibrosis. Mice transgenic to express EST showed renal fibrosis at a young age. One month delivery of EST via minipumps to young mice showed increased renal fibrosis that became more robust when superimposed on folic acid-induced nephropathy. Upregulated TG2 and impaired renal function were apparent with EST delivery combined with folic acid-induced nephropathy. Subcapsular injection of TG2 and/or EST into kidneys of young mice not only induced interstitial fibrosis, but also increased the proportion of senescent cells. Thus, kidney fibrosis in aging may represent a natural outcome of upregulated EST and TG2, but more likely it appears to be a result of cumulative stresses occurring on the background of synergistically acting geronic (aging) proteins, EST and TG2. PMID:27165830

Unconventional secretion of tissue transglutaminase involves phospholipid-dependent delivery into recycling endosomes.

Directory of Open Access Journals (Sweden)

Evgeny A Zemskov

2011-04-01

Full Text Available Although endosomal compartments have been suggested to play a role in unconventional protein secretion, there is scarce experimental evidence for such involvement. Here we report that recycling endosomes are essential for externalization of cytoplasmic secretory protein tissue transglutaminase (tTG. The de novo synthesized cytoplasmic tTG does not follow the classical ER/Golgi-dependent secretion pathway, but is targeted to perinuclear recycling endosomes, and is delivered inside these vesicles prior to externalization. On its route to the cell surface tTG interacts with internalized β1 integrins inside the recycling endosomes and is secreted as a complex with recycled β1 integrins. Inactivation of recycling endosomes, blocking endosome fusion with the plasma membrane, or downregulation of Rab11 GTPase that controls outbound trafficking of perinuclear recycling endosomes, all abrogate tTG secretion. The initial recruitment of cytoplasmic tTG to recycling endosomes and subsequent externalization depend on its binding to phosphoinositides on endosomal membranes. These findings begin to unravel the unconventional mechanism of tTG secretion which utilizes the long loop of endosomal recycling pathway and indicate involvement of endosomal trafficking in non-classical protein secretion.

Anti-Transglutaminase 6 Antibodies in Children and Young Adults with Cerebral Palsy

Directory of Open Access Journals (Sweden)

Reidun Stenberg

2014-01-01

Full Text Available Objectives. We have previously reported a high prevalence of gluten-related serological markers (GRSM in children and young adults with cerebral palsy (CP. The majority had no enteropathy to suggest coeliac disease (CD. Antibodies against transglutaminase 6 (anti-TG6 represent a new marker associated with gluten-related neurological dysfunction. The aim of this study was to investigate the prevalence of anti-TG6 antibodies in this group of individuals with an early neurological injury resulting in CP. Materials and Methods. Sera from 96 patients with CP and 36 controls were analysed for IgA/IgG class anti-TG6 by ELISA. Results. Anti-TG6 antibodies were found in 12/96 (13% of patients with CP compared to 2/36 (6% in controls. The tetraplegic subgroup of CP had a significantly higher prevalence of anti-TG6 antibodies 6/17 (35% compared to the other subgroups and controls. There was no correlation of anti-TG6 autoantibodies with seropositivity to food proteins including gliadin. Conclusions. An early brain insult and associated inflammation may predispose to future development of TG6 autoimmunity.

Microbial examination of anaerobic sludge adaptation to animal slurry.

Science.gov (United States)

Moset, V; Cerisuelo, A; Ferrer, P; Jimenez, A; Bertolini, E; Cambra-López, M

2014-01-01

The objective of this study was to evaluate changes in the microbial population of anaerobic sludge digesters during the adaptation to pig slurry (PS) using quantitative real-time polymerase chain reaction (qPCR) and qualitative scanning electron microscopy (SEM). Additionally, the relationship between microbial parameters and sludge physicochemical composition and methane yield was examined. Results showed that the addition of PS to an unadapted thermophilic anaerobic digester caused an increase in volatile fatty acids (VFA) concentration, a decrease in removal efficiency and CH4 yield. Additionally, increases in total bacteria and total archaea were observed using qPCR. Scanning electron micrographs provided a general overview of the sludge's cell morphology, morphological diversity and degree of organic matter degradation. A change in microbial morphotypes from homogeneous cell morphologies to a higher morphological diversity, similar to that observed in PS, was observed with the addition of PS by SEM. Therefore, the combination of qPCR and SEM allowed expanding the knowledge about the microbial adaptation to animal slurry in thermophilic anaerobic digesters.

Conversion of Wastes into Bioelectricity and Chemicals by Using Microbial Electrochemical Technologies

KAUST Repository

Logan, B. E.; Rabaey, K.

2012-01-01

Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a

Electricity generation from the mud by using microbial fuel cell

Directory of Open Access Journals (Sweden)

Idris Sitinoor Adeib

2016-01-01

Full Text Available Microbial fuel cells (MFCs is a bio-electrochemical device that harnesses the power of respiring microbes to convert organic substrates directly into electrical energy. This is achieved when bacteria transfer electrons to an electrode rather than directly to an electron acceptor. Their technical feasibility has recently been proven and there is great enthusiasm in the scientific community that MFCs could provide a source of “green electricity”. Microbial fuel cells work by allowing bacteria to do what they do best, oxidize and reduce organic molecules. Bacterial respiration is basically one big redox reaction in which electrons are being moved around. The objective is to generate electricity throughout the biochemical process using chemical waste basically sludge, via microbial fuel cells. The methodology includes collecting sludge from different locations, set up microbial fuel cells with the aid of salt bridge and observing the results in voltage measurement. The microbial fuel cells consist of two chambers, iron electrodes, copper wire, air pump (to increase the efficiency of electron transfer, water, sludge and salt bridge. After several observations, it is seen that this MFC can achieve up until 202 milivolts (0.202volts with the presence of air pump. It is proven through the experiments that sludge from different locations gives different results in term of the voltage measurement. This is basically because in different locations of sludge contain different type and amount of nutrients to provide the growth of bacteria. Apart from that, salt bridge also play an important role in order to transport the proton from cathode to anode. A longer salt bridge will give a higher voltage compared to a short salt bridge. On the other hand, the limitations that this experiment facing is the voltage that being produced did not last long as the bacteria activity slows down gradually and the voltage produced are not really great in amount. Lastly to

Polyphasic characterization of a PCP-to-phenol dechlorinating microbial community enriched from paddy soil

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Naoko [EcoTopia Science Institute, Nagoya University Nagoya 464-8603 (Japan)]. E-mail: ysd75@esi.nagoya-u.ac.jp; Yoshida, Yukina [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Handa, Yuko [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Kim, Hyo-Keun [Korea Ginseng and Tobacco Research Institute, Taejon 305-345 (Korea, Republic of); Ichihara, Shigeyuki [Faculty of Agriculture, Meijo University, Nagoya 468-8502 (Japan); Katayama, Arata [EcoTopia Science Institute, Nagoya University Nagoya 464-8603 (Japan); Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan)

2007-08-01

Dechlorination of PCP has been observed previously under anaerobic condition in paddy soil. However, there is poor information about the dechlorination pathway of PCP and the microbial community associated with the PCP dechlorination in paddy soil. In this study, an anaerobic microbial community dechlorinating PCP was enriched by serial transfers from a paddy soil using a medium containing PCP, lactate and the steam-sterilized paddy soil. The enriched microbial community dechlorinated PCP completely to phenol under the anaerobic condition by a dechlorinating pathway as follows; PCP {sup {yields}} 2,3,4,5-tetrachlorophenol {sup {yields}} 3,4,5-trichlorophenol {sup {yields}} 3,5-dichlorophenol {sup {yields}} 3-chlorophenol {sup {yields}} phenol. Intermediate products such as 3-chlorophenol were not accumulated, which were immediately dechlorinated to phenol. The enriched microbial community was characterized physiologically by testing the effects of electron donors and electron acceptors on the dechlorinating activity. The dechlorinating activity was promoted with lactate, pyruvate, and hydrogen as electron donors but not with acetate. Electron acceptors, nitrate and sulphate, inhibited the dechlorinating activity competitively but not iron (III). The microbial group associated with the anaerobic dechlorination was characterized by the effect of specific inhibitors on the PCP dechlorination. Effects of specific metabolic inhibitors and antibiotics indicated the involvement of Gram-positive spore-forming bacteria with the PCP dechlorinating activity, which was represented as bacteria of phylum Firmicutes. The structure of the microbial community was characterized by fluorescence in situ hybridization, quinone profiling, and PCR-DGGE (denaturing gel gradient electrophoresis). The combined results indicated the predominance of Clostridium species of phylum Firmicutes in the microbial community. Desulfitobacterium spp. known as anaerobic Gram-positive spore

Polyphasic characterization of a PCP-to-phenol dechlorinating microbial community enriched from paddy soil

International Nuclear Information System (INIS)

Yoshida, Naoko; Yoshida, Yukina; Handa, Yuko; Kim, Hyo-Keun; Ichihara, Shigeyuki; Katayama, Arata

2007-01-01

Dechlorination of PCP has been observed previously under anaerobic condition in paddy soil. However, there is poor information about the dechlorination pathway of PCP and the microbial community associated with the PCP dechlorination in paddy soil. In this study, an anaerobic microbial community dechlorinating PCP was enriched by serial transfers from a paddy soil using a medium containing PCP, lactate and the steam-sterilized paddy soil. The enriched microbial community dechlorinated PCP completely to phenol under the anaerobic condition by a dechlorinating pathway as follows; PCP → 2,3,4,5-tetrachlorophenol → 3,4,5-trichlorophenol → 3,5-dichlorophenol → 3-chlorophenol → phenol. Intermediate products such as 3-chlorophenol were not accumulated, which were immediately dechlorinated to phenol. The enriched microbial community was characterized physiologically by testing the effects of electron donors and electron acceptors on the dechlorinating activity. The dechlorinating activity was promoted with lactate, pyruvate, and hydrogen as electron donors but not with acetate. Electron acceptors, nitrate and sulphate, inhibited the dechlorinating activity competitively but not iron (III). The microbial group associated with the anaerobic dechlorination was characterized by the effect of specific inhibitors on the PCP dechlorination. Effects of specific metabolic inhibitors and antibiotics indicated the involvement of Gram-positive spore-forming bacteria with the PCP dechlorinating activity, which was represented as bacteria of phylum Firmicutes. The structure of the microbial community was characterized by fluorescence in situ hybridization, quinone profiling, and PCR-DGGE (denaturing gel gradient electrophoresis). The combined results indicated the predominance of Clostridium species of phylum Firmicutes in the microbial community. Desulfitobacterium spp. known as anaerobic Gram-positive spore-forming bacteria dechlorinating PCP were not detected by PCR using a

Deep subsurface microbial processes

Science.gov (United States)

Lovley, D.R.; Chapelle, F.H.

1995-01-01

Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

Influences of dissolved oxygen concentration on biocathodic microbial communities in microbial fuel cells.

Science.gov (United States)

Rago, Laura; Cristiani, Pierangela; Villa, Federica; Zecchin, Sarah; Colombo, Alessandra; Cavalca, Lucia; Schievano, Andrea

2017-08-01

Dissolved oxygen (DO) at cathodic interface is a critical factor influencing microbial fuel cells (MFC) performance. In this work, three MFCs were operated with cathode under different DO conditions: i) air-breathing (A-MFC); ii) water-submerged (W-MFC) and iii) assisted by photosynthetic microorganisms (P-MFC). A plateau of maximum current was reached at 1.06±0.03mA, 1.48±0.06mA and 1.66±0.04mA, increasing respectively for W-MFC, P-MFC and A-MFC. Electrochemical and microbiological tools (Illumina sequencing, confocal microscopy and biofilm cryosectioning) were used to explore anodic and cathodic biofilm in each MFC type. In all cases, biocathodes improved oxygen reduction reaction (ORR) as compared to abiotic condition and A-MFC was the best performing system. Photosynthetic cultures in the cathodic chamber supplied high DO level, up to 16mg O2 L -1 , which sustained aerobic microbial community in P-MFC biocathode. Halomonas, Pseudomonas and other microaerophilic genera reached >50% of the total OTUs. The presence of sulfur reducing bacteria (Desulfuromonas) and purple non-sulfur bacteria in A-MFC biocathode suggested that the recirculation of sulfur compounds could shuttle electrons to sustain the reduction of oxygen as final electron acceptor. The low DO concentration limited the cathode in W-MFC. A model of two different possible microbial mechanisms is proposed which can drive predominantly cathodic ORR. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemical evaluation of Ti/TiO{sub 2}-polyaniline anodes for microbial fuel cells using hypersaline microbial consortia for synthetic-wastewater treatment

Energy Technology Data Exchange (ETDEWEB)

Benetton, X.D.; Navarro-Avila, S.G. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Biotecnologia y Bioingenieria; Carrera-Figueiras, C. [Univ. Autonoma de Yucatan, Yucatan (Mexico). Quimica Fundamental y Aplicada

2010-07-01

This paper described the development of a titanium (Ti/TiO{sub 2}) polyaniline composite electrode. The electrode was designed for use with a microbial fuel cell (MFC) that generated electricity through the microbial biodegradation of organic compounds. A modified NBAF medium was used with a 20 mM acetate as an electron donor and 53 mM fumarate as an electron acceptor for a period of 96 hours at 37 degrees C. Strains were cultured under strict anaerobic conditions. Two microbial cultures were used: (1) pure cultures of Geobacter sulfur-reducens; and (2) an uncharacterized stable microbial consortia isolated from hypersaline swamp sediments. The anodes were made with an emeraldine form of PANI deposited over Ti/TiO{sub 2} electrodes. Electrochemical impedance spectroscopy (EIS) monitoring was used to determine the open circuit potential of the MFC. Negative real impedances were obtained and reproduced in all systems studied with the Ti/TiO{sub 2}-PANI anodes. The highest power density was obtained using the Geobacter sulfur-reducens culture. Further research is needed to study the mechanisms that contribute to the occurrence of negative real impedances. 23 refs., 1 tab., 5 figs.

Serum transglutaminase 3 antibodies correlate with age at celiac disease diagnosis.

Science.gov (United States)

Salmi, Teea T; Kurppa, Kalle; Hervonen, Kaisa; Laurila, Kaija; Collin, Pekka; Huhtala, Heini; Saavalainen, Päivi; Sievänen, Harri; Reunala, Timo; Kaukinen, Katri

2016-06-01

Transglutaminase (TG)2 is the autoantigen in celiac disease, but also TG3 antibodies have been detected in the serum of celiac disease patients. To investigate the correlations between serum TG3 antibodies and clinical and histological manifestations of celiac disease and to assess gluten-dependency of TG3 antibodies. Correlations between serum TG3 antibody levels measured from 119 adults and children with untreated coeliac disease and the demographic data, clinical symptoms, celiac antibodies, histological data and results of laboratory tests and bone mineral densities were tested. TG3 antibodies were reinvestigated in 97 celiac disease patients after 12 months on a gluten-free diet (GFD). TG3 antibody titers were shown to correlate with the age at celiac disease diagnosis. Further, negative correlation with TG3 antibodies and intestinal γδ+ cells at diagnosis and on GFD was detected. Correlations were not detected with the clinical manifestation of celiac disease, TG2 or endomysial autoantibodies, laboratory values, severity of mucosal villous atrophy, associated diseases or complications. TG3 antibody titers decreased on GFD in 56% of the TG3 antibody positive patients. Serum TG3 antibody positivity in celiac disease increases as the diagnostic age rises. TG3 antibodies did not show similar gluten-dependency as TG2 antibodies. Copyright © 2016 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Humic substances-mediated microbial reductive dehalogenation of triclosan

Science.gov (United States)

Wang, L.; Xu, S.; Yang, Y.

2015-12-01

The role of natural organic matter in regulating the redox reactions as an electron shuttle has received lots of attention, because it can significantly affect the environmental degradation of contaminants and biogeochemical cycles of major elements. However, up to date, limited studies examined the role of natural organic matter in affecting the microbial dehalogenation of emergent organohalides, a critical detoxification process. In this study, we investigated the humic substance (HS)-mediated microbial dehalogenation of triclosan, a widely used antimicrobial agent. We found that the presence of HS stimulated the microbial degradation of triclosan by Shewanella putrefaciens CN-32. In the absence of HS, the triclosan was degraded gradually, achieving 8.6% residual at 8 days. With HS, the residual triclosan was below 2% after 4 days. Cl- was confirmed by ion chromatography analysis, but the dehalogenation processes and other byproducts warrant further investigations. The impact of HS on the degradation of triclosan was highly dependent on the concentration of HS. When the HS was below 15 mg/L, the degradation rate constant for triclosan increased with the organic carbon concentration. Beyond that point, the increased organic carbon concentration decreased the degradation of triclosan. Microbially pre-reduced HS abiotically reduced triclosan, testifying the electron shuttling processes. These results indicate that dissolved organic matter plays a dual role in regulating the degradation of triclosan: it mediates electron transport and inhibits the bioavailability through complexation. Such novel organic matter-mediated reactions for organohalides are important for evaluating the natural attenuation of emergent contaminants and designing cost-effective engineering treatment.

Treatment of foods with 'soft-electrons' (low-energy electrons)

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Toru [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan); Todoriki, Setsuko [National Food Research Institute (NFRI), Tsukuba, Ibaraki (Japan)

2003-02-01

Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

Enhanced microbial reduction of vanadium (V) in groundwater with bioelectricity from microbial fuel cells

Science.gov (United States)

Hao, Liting; Zhang, Baogang; Tian, Caixing; Liu, Ye; Shi, Chunhong; Cheng, Ming; Feng, Chuanping

2015-08-01

Bioelectricity generated from the microbial fuel cell (MFC) is applied to the bioelectrical reactor (BER) directly to enhance microbial reduction of vanadium (V) (V(V)) in groundwater. With the maximum power density of 543.4 mW m-2 from the MFC, V(V) removal is accelerated with efficiency of 93.6% during 12 h operation. Higher applied voltage can facilitate this process. V(V) removals decrease with the increase of initial V(V) concentration, while extra addition of chemical oxygen demand (COD) has little effect on performance improvement. Microbial V(V) reduction is enhanced and then suppressed with the increase of conductivity. High-throughput 16S rRNA gene pyrosequencing analysis implies the accumulated Enterobacter and Lactococcus reduce V(V) with products from fermentative microorganisms such as Macellibacteroides. The presentation of electrochemically active bacteria as Enterobacter promotes electron transfers. This study indicates that application of bioelectricity from MFCs is a promising strategy to improve the efficiency of in-situ bioremediation of V(V) polluted groundwater.

Energy Harvesting From River Sediment Using a Microbial Fuel Cell: Preliminary Results

Directory of Open Access Journals (Sweden)

Philippe Namour

2014-05-01

Full Text Available We have built a sedimentary fuel cell or Sediment Microbial Fuel Cell (SMFC. The device works on the principle of microbial fuel cells by exploiting directly the energy contained in sedimentary organic matter. It converts in electricity the sediment potential, thanks to microorganisms able to waste electrons from their metabolism directly to a solid anode instead of their natural electron acceptors, such as oxygen or nitrate. The sediment microbial fuel cell was made of a non-corrodible anode (graphite buried in anoxic sediments layer and connected via an electrical circuit to a cathode installed in surface water. We present the first results of laboratory sedimentary fuel cell and a prototype installed in the river.

Glycation and transglutaminase mediated glycosylation of fish gelatin peptides with glucosamine enhance bioactivity.

Science.gov (United States)

Hong, Pui Khoon; Gottardi, Davide; Ndagijimana, Maurice; Betti, Mirko

2014-01-01

A mixture of novel glycopeptides from glycosylation between cold water fish skin gelatin hydrolysates and glucosamine (GlcN) via transglutaminase (TGase), as well as glycation between fish gelatin hydrolysate and GlcN were identified by their pattern of molecular distribution using MALDI-TOF-MS. Glycated/glycosylated hydrolysates showed superior bioactivity to their original hydrolysates. Alcalase-derived fish skin gelatin hydrolysate glycosylated with GlcN in the presence of TGase at 25°C (FAT25) possessed antioxidant activity when tested in a linoleic acid oxidation system, when measured according to its 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and when tested at the cellular level with human hepatocarcinoma (HepG2) cells as target cells. In addition, Alcalase-derived glycosylated hydrolysates showed specificity toward the inhibition of Escherichia coli (E. coli). The Flavourzyme-derived glycopeptides prepared at 37°C (FFC37 and FFT37) showed better DPPH scavenging activity than their native hydrolysates. The glycated Flavourzyme-derived hydrolysates were found to act as potential antimicrobial agents when incubated with E. coli and Bacillus subtilis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Set anode potentials affect the electron fluxes and microbial community structure in propionate-fed microbial electrolysis cells

KAUST Repository

Rao, Hari Ananda; Katuri, Krishna; Logan, Bruce E.; Saikaly, Pascal

2016-01-01

, but their relative abundance varied among the tested SAPs. Microbial community analysis implies that complete degradation of propionate in all the tested SAPs was facilitated by syntrophic interactions between fermenters and Geobacter at the anode and ferementers

Microbial community analysis of perchlorate-reducing cultures growing on zero-valent iron

International Nuclear Information System (INIS)

Son, Ahjeong; Schmidt, Carl J.; Shin, Hyejin; Cha, Daniel K.

2011-01-01

Anaerobic microbial mixed cultures demonstrated its ability to completely remove perchlorate in the presence of zero-valent iron. In order to understand the major microbial reaction in the iron-supported culture, community analysis comprising of microbial fatty acids and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) techniques was performed for perchlorate reducing cultures. Analysis of fatty acid methyl esters (FAMEs) and subsequent principal component analysis (PCA) showed clear distinctions not only between iron-supported perchlorate reducing culture and seed bacteria, but also among perchlorate-reducing cultures receiving different electron donors. The DGGE pattern targeting the chlorite dismutase (cld) gene showed that iron-supported perchlorate reducing culture is similar to hydrogen-fed cultures as compared to acetate-fed culture. The phylogenetic tree suggested that the dominant microbial reaction may be a combination of the autotrophic and heterotrophic reduction of perchlorate. Both molecular and chemotaxonomic experimental results support further understanding in the function of zero-valent iron as an adequate electron source for enhancing the microbial perchlorate reduction in natural and engineered systems.

Microbial community analysis of perchlorate-reducing cultures growing on zero-valent iron

Energy Technology Data Exchange (ETDEWEB)

Son, Ahjeong, E-mail: ason@auburn.edu [Department of Civil Engineering, Auburn University, Auburn, AL 36849 (United States); Schmidt, Carl J. [Department of Animal and Food Sciences, University of Delaware, Newark, DE 19716 (United States); Shin, Hyejin [Department of Mathematics and Statistics, Auburn University, Auburn, AL 36849 (United States); Cha, Daniel K. [Department of Civil and Environmental Engineering, University of Delaware, Newark, DE 19716 (United States)

2011-01-30

Anaerobic microbial mixed cultures demonstrated its ability to completely remove perchlorate in the presence of zero-valent iron. In order to understand the major microbial reaction in the iron-supported culture, community analysis comprising of microbial fatty acids and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) techniques was performed for perchlorate reducing cultures. Analysis of fatty acid methyl esters (FAMEs) and subsequent principal component analysis (PCA) showed clear distinctions not only between iron-supported perchlorate reducing culture and seed bacteria, but also among perchlorate-reducing cultures receiving different electron donors. The DGGE pattern targeting the chlorite dismutase (cld) gene showed that iron-supported perchlorate reducing culture is similar to hydrogen-fed cultures as compared to acetate-fed culture. The phylogenetic tree suggested that the dominant microbial reaction may be a combination of the autotrophic and heterotrophic reduction of perchlorate. Both molecular and chemotaxonomic experimental results support further understanding in the function of zero-valent iron as an adequate electron source for enhancing the microbial perchlorate reduction in natural and engineered systems.

Effectiveness of electron beam microbial decontamination and change of essential oil components in fennel

International Nuclear Information System (INIS)

Yamaoki, Rumi; Kimura, Shojiro; Ohtsu, Naomi; Chikuta, Yasuhiro; Mino, Yoshiki; Aoki, Kenji; Ohta, Masatoshi

2008-01-01

The effectiveness of electron beam (EB) disinfection and sterilization technology and the changes of essential oil components in fennel were investigated. The absorbed dose was maximal at a depth of 0.9-1.0 g/cm 2 , which was 130% of the surface dose of 15 kGy in packed fennel irradiated with 5 MeV EB in a downward direction, and decreased in the deepest layer. As a result, in a fennel bacterial count of 10 5 cfu/g, a microbial contamination level below 1.0x10 3 cfu/g was obtained at a packing depth of 2.3 g/cm 2 and at the absorbed dose of more than 3 kGy. The bacteria in fennel were highly sensitive to EB irradiation. Furthermore, EB irradiation had no effect on the essential oil content of fennel, and no change of the essential oil components was found at the irradiation level necessary for decontamination. (author)

Electricity generation by Enterobacter cloacae SU-1 in mediator less microbial fuel cell

Energy Technology Data Exchange (ETDEWEB)

Samrot, Antony V.; Senthilkumar, P.; Pavankumar, K.; Akilandeswari, G.C. [Department of Biotechnology, Sathyabama University, Rajiv Gandhi Salai, Chennai, Tamilnadu (India); Rajalakshmi, N.; Dhathathreyan, K.S. [Center for Fuel Cell Technology ARCI, IITM Research Park, Phase I, 2nd Floor, 6 Kanagam Road, Tharamani, Chennai 600 113, Tamilnadu (India)

2010-08-15

We have investigated a Enterobacter cloacae SU-1, bacteria for mediator less microbial fuel cell with different carbon sources and is found to be more effective as the microorganism is able to transfer electrons directly (exo-electrogenic organism) via the cytochromes or the ubiquinone. These carriers of electrons are in form of stable reversible redox couples, not biologically degraded and not toxic to cell. The major advantage of mediator less microbial fuel cells emphasize that additives in the anolyte is not compatible with the purpose of water purification. The anode chamber with the bacteria is maintained under anaerobic conditions so that the bacteria will undergo anaerobic biochemical pathways like Glycolysis, TCA cycle, Electron Transport Chain (ETC) where electrons and protons are released. Here protons are released in TCA cycle and whereas electrons are released from ETC. The mediator less microbial fuel cell delivered an open circuit potential (OCP) of 0.93 V and power of 3 mW/sq cm. During power generation from the microbes, there was a drop in coulombic efficiency in terms of fluctuations during drawing power, as the carbon source is being utilized for the cell growth. (author)

Simulated Carbon Cycling in a Model Microbial Mat.

Science.gov (United States)

Decker, K. L.; Potter, C. S.

2006-12-01

We present here the novel addition of detailed organic carbon cycling to our model of a hypersaline microbial mat ecosystem. This ecosystem model, MBGC (Microbial BioGeoChemistry), simulates carbon fixation through oxygenic and anoxygenic photosynthesis, and the release of C and electrons for microbial heterotrophs via cyanobacterial exudates and also via a pool of dead cells. Previously in MBGC, the organic portion of the carbon cycle was simplified into a black-box rate of accumulation of simple and complex organic compounds based on photosynthesis and mortality rates. We will discuss the novel inclusion of fermentation as a source of carbon and electrons for use in methanogenesis and sulfate reduction, and the influence of photorespiration on labile carbon exudation rates in cyanobacteria. We will also discuss the modeling of decomposition of dead cells and the ultimate release of inorganic carbon. The detailed modeling of organic carbon cycling is important to the accurate representation of inorganic carbon flux through the mat, as well as to accurate representation of growth models of the heterotrophs under different environmental conditions. Because the model ecosystem is an analog of ancient microbial mats that had huge impacts on the atmosphere of early earth, this MBGC can be useful as a biological component to either early earth models or models of other planets that potentially harbor life.

Effect of Ionizing irradiation on microbial load and quality and sensory characteristics of chamomile (Matricaria recutita, Anthemis nobilis)

International Nuclear Information System (INIS)

Al-Bachir, M.

2014-03-01

A study was conducted to investigate the effect of gamma irradiation and electron beam on microbial physical chemical and sensorial properties of chamomile. Powders of chamomile were exposed to 10 and 20 kGy of gamma irradiation and electron bean. Microbial load and moisture of powder, extraction rate physical chemical and sensorial properties of chamomile extract were evaluated immediately after treatment and after 12 months of storage. Results indicated that total microbial count of chamomile powder (control sample), including coliform were relatively high irradiation reduced the total count and total coliform. Electron beam was more effective in reducing the microbial load than gamma irradiation. No considerable changes in physico-chemical properties of extract produced from chamomile powder treated with low doses (10 kGy) while some changes were indicated in extract produced from chamomile powder treated with low doses (20 kGy) of gamma irradiation or electron beam. No differences were verified in the overall of sensorial (color, flavor, texture, and taste) properties of chamomile extracts after irradiation with 10 and 20 kGy of gamma irradiation or electron beam.(author)

Microbial fuel cell based on electroactive sulfate-reducing biofilm

International Nuclear Information System (INIS)

Angelov, Anatoliy; Bratkova, Svetlana; Loukanov, Alexandre

2013-01-01

Highlights: ► Regulation and management of electricity generation by variation of residence time. ► Design of microbial fuel cell based on electroactive biofilm on zeolite. ► Engineering solution for removing of the obtained elemental sulfur. - abstract: A two chambered laboratory scale microbial fuel cell (MFC) has been developed, based on natural sulfate-reducing bacterium consortium in electroactive biofilm on zeolite. The MFC utilizes potassium ferricyanide in the cathode chamber as an electron acceptor that derives electrons from the obtained in anode chamber H 2 S. The molecular oxygen is finally used as a terminal electron acceptor at cathode compartment. The generated power density was 0.68 W m −2 with current density of 3.2 A m −2 at 150 Ω electrode resistivity. The hydrogen sulfide itself is produced by microbial dissimilative sulfate reduction process by utilizing various organic substrates. Finally, elemental sulfur was identified as the predominant final oxidation product in the anode chamber. It was removed from MFC through medium circulation and gathering in an external tank. This report reveals dependence relationship between the progress of general electrochemical parameters and bacterial sulfate-reduction rate. The presented MFC design can be used for simultaneous sulfate purification of mining drainage wastewater and generation of renewable electricity

From chemolithoautotrophs to electrolithoautotrophs: CO2 fixation by Fe(II)-oxidizing bacteria coupled with direct uptake of electrons from solid electron sources.

Science.gov (United States)

Ishii, Takumi; Kawaichi, Satoshi; Nakagawa, Hirotaka; Hashimoto, Kazuhito; Nakamura, Ryuhei

2015-01-01

At deep-sea vent systems, hydrothermal emissions rich in reductive chemicals replace solar energy as fuels to support microbial carbon assimilation. Until recently, all the microbial components at vent systems have been assumed to be fostered by the primary production of chemolithoautotrophs; however, both the laboratory and on-site studies demonstrated electrical current generation at vent systems and have suggested that a portion of microbial carbon assimilation is stimulated by the direct uptake of electrons from electrically conductive minerals. Here we show that chemolithoautotrophic Fe(II)-oxidizing bacterium, Acidithiobacillus ferrooxidans, switches the electron source for carbon assimilation from diffusible Fe(2+) ions to an electrode under the condition that electrical current is the only source of energy and electrons. Site-specific marking of a cytochrome aa3 complex (aa3 complex) and a cytochrome bc1 complex (bc1 complex) in viable cells demonstrated that the electrons taken directly from an electrode are used for O2 reduction via a down-hill pathway, which generates proton motive force that is used for pushing the electrons to NAD(+) through a bc1 complex. Activation of carbon dioxide fixation by a direct electron uptake was also confirmed by the clear potential dependency of cell growth. These results reveal a previously unknown bioenergetic versatility of Fe(II)-oxidizing bacteria to use solid electron sources and will help with understanding carbon assimilation of microbial components living in electronically conductive chimney habitats.

Bio-Electron-Fenton (BEF) process driven by microbial fuel cells for triphenyltin chloride (TPTC) degradation

International Nuclear Information System (INIS)

Yong, Xiao-Yu; Gu, Dong-Yan; Wu, Yuan-Dong; Yan, Zhi-Ying; Zhou, Jun; Wu, Xia-Yuan; Wei, Ping; Jia, Hong-Hua; Zheng, Tao; Yong, Yang-Chun

2017-01-01

Graphical abstract: Schematic diagram of the Bio-Electron-Fenton (BEF) process for TPTC degradation. - Highlights: • A Bio-Electro-Fenton process was performed for TPTC degradation. • TPTC removal efficiency achieved 78.32 ± 2.07% within 100 h. • The TPTC degradation rate (0.775 ± 0.021 μmol L"−"1 h"−"1) was much higher than previous reports. - Abstract: The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H_2O_2 to a maximum of 135.96 μmol L"−"1 at the Fe@Fe_2O_3_(_*_)/graphite felt composite cathode, which further reacted with leached Fe"2"+ to produce hydroxyl radicals. While 100 μmol L"−"1 TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32 ± 2.07%, with a rate of 0.775 ± 0.021 μmol L"−"1 h"−"1. This Bio-Electron-Fenton driving TPTC degradation might involve in Sn−C bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO_2. This study provides an energy saving and efficient approach for TPTC degradation.

Electron acceptor-based regulation of microbial greenhouse gas production from thawing permafrost

DEFF Research Database (Denmark)

Bak, Ebbe Norskov; Jones, Eleanor; Yde, Jacob Clement

layer as well in the permafrost. These investigations are accompanied by characterization of the carbon, iron and sulfate content in the soil and will be followed by characterization of the microbial community structure. The aim of this study is to get a better understanding of how the availability...... of sulfate and iron and the microbial community structure regulate the production of CO2 and CH4 in thawing permafrost, and to elucidate how the rate of the organic carbon degradation changes with depth in permafrost-affected soils. This study improves our understanding of climate feedback mechanisms...

Microbial catabolic activities are naturally selected by metabolic energy harvest rate.

Science.gov (United States)

González-Cabaleiro, Rebeca; Ofiţeru, Irina D; Lema, Juan M; Rodríguez, Jorge

2015-12-01

The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate.

Celiac disease or positive tissue transglutaminase antibodies in patients undergoing renal biopsies.

Science.gov (United States)

Nurmi, Rakel; Metso, Martti; Pörsti, Ilkka; Niemelä, Onni; Huhtala, Heini; Mustonen, Jukka; Kaukinen, Katri; Mäkelä, Satu

2018-01-01

An association between celiac disease and renal diseases has been suggested, but the results are controversial. To investigate the prevalence of celiac disease autoimmunity among individuals undergoing renal biopsies and to evaluate whether co-existent celiac autoimmunity influences the clinical outcome of the renal disease. The prevalence of celiac autoimmunity (previous diagnosis of celiac disease or positive tissue transglutaminase antibodies) was determined in 827 consecutive patients undergoing kidney biopsies due to clinical indications. Up to 15 years' follow-up data on kidney function and co-morbidities were obtained. Celiac autoimmunity was found in 45 (5.4%) patients. Among the IgA nephropathy patients, 8.2% of had celiac autoimmunity. At the time of kidney biopsy and after a median follow-up of 5 to 6 years, renal function measured by estimated glomerular filtration rate (eGFR) was inferior in IgA nephropathy patients with celiac autoimmunity compared to those without it (P=0.048 and P=0.022, respectively). The prevalence of celiac autoimmunity seems to be high in patients undergoing renal biopsies, especially in patients with IgA nephropathy. Such autoimmunity may be associated with worse renal function in IgA nephropathy. Hence the co-existence of celiac disease should be taken into consideration when treating patients with renal diseases. Copyright © 2017 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

Transglutaminase 2 expression is increased as a function of malignancy grade and negatively regulates cell growth in meningioma.

Directory of Open Access Journals (Sweden)

Yin-Cheng Huang

Full Text Available Most meningiomas are benign, but some clinical-aggressive tumors exhibit brain invasion and cannot be resected without significant complications. To identify molecular markers for these clinically-aggressive meningiomas, we performed microarray analyses on 24 primary cultures from 21 meningiomas and 3 arachnoid membranes. Using this approach, increased transglutaminase 2 (TGM2 expression was observed, which was subsequently validated in an independent set of 82 meningiomas by immunohistochemistry. Importantly, the TGM2 expression level was associated with increasing WHO malignancy grade as well as meningioma recurrence. Inhibition of TGM2 function by siRNA or cystamine induced meningioma cell death, which was associated with reduced AKT phosphorylation and caspase-3 activation. Collectively, these findings suggest that TGM2 expression increases as a function of malignancy grade and tumor recurrence and that inhibition of TGM2 reduces meningioma cell growth.

Extracellular electron transfer mechanisms between microorganisms and minerals

Energy Technology Data Exchange (ETDEWEB)

Shi, Liang; Dong, Hailiang; Reguera, Gemma; Beyenal, Haluk; Lu, Anhuai; Liu, Juan; Yu, Han-Qing; Fredrickson, James K.

2016-08-30

Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials.

Microbial O2 consumption in the Aespoe tunnel

International Nuclear Information System (INIS)

Kotelnikova, S.; Pedersen, Karsten

1998-04-01

The report presents data on microbial O 2 reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O 2 intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O 2 reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O 2 reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O 2 reduction confirming the biogenic nature of the reduction. The populations developed O 2 reduction rates and capacity depending on the initial concentration of dissolved O 2 reduction. Rates of O 2 reduction ranged from 0.32 to 4.5 μM/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 μM of dissolved O 2 ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O 2 both at 30 deg C and 60 deg C. At 16 deg C no delay in O 2 consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O 2 . Some bacteria use Hg or CH 4 as electron donor instead of organic matter, which means that microbial O 2 reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH 4 oxidation rates ranged between 3.00 and 220 nM CH 4 per litre per day. Comparison of the total O 2 reducing activities by gas chromatography and

Patterns in wetland microbial community composition and functional gene repertoire associated with methane emissions.

Science.gov (United States)

He, Shaomei; Malfatti, Stephanie A; McFarland, Jack W; Anderson, Frank E; Pati, Amrita; Huntemann, Marcel; Tremblay, Julien; Glavina del Rio, Tijana; Waldrop, Mark P; Windham-Myers, Lisamarie; Tringe, Susannah G

2015-05-19

Wetland restoration on peat islands previously drained for agriculture has potential to reverse land subsidence and sequester atmospheric carbon dioxide as peat accretes. However, the emission of methane could potentially offset the greenhouse gas benefits of captured carbon. As microbial communities play a key role in governing wetland greenhouse gas fluxes, we are interested in how microbial community composition and functions are associated with wetland hydrology, biogeochemistry, and methane emission, which is critical to modeling the microbial component in wetland methane fluxes and to managing restoration projects for maximal carbon sequestration. Here, we couple sequence-based methods with biogeochemical and greenhouse gas measurements to interrogate microbial communities from a pilot-scale restored wetland in the Sacramento-San Joaquin Delta of California, revealing considerable spatial heterogeneity even within this relatively small site. A number of microbial populations and functions showed strong correlations with electron acceptor availability and methane production; some also showed a preference for association with plant roots. Marker gene phylogenies revealed a diversity of major methane-producing and -consuming populations and suggested novel diversity within methanotrophs. Methanogenic archaea were observed in all samples, as were nitrate-, sulfate-, and metal-reducing bacteria, indicating that no single terminal electron acceptor was preferred despite differences in energetic favorability and suggesting spatial microheterogeneity and microniches. Notably, methanogens were negatively correlated with nitrate-, sulfate-, and metal-reducing bacteria and were most abundant at sampling sites with high peat accretion and low electron acceptor availability, where methane production was highest. Wetlands are the largest nonanthropogenic source of atmospheric methane but also a key global carbon reservoir. Characterizing belowground microbial communities

Physicochemical Properties of Meat Batter Added with Edible Silkworm Pupae (Bombyx mori) and Transglutaminase

Science.gov (United States)

Choi, Yun-Sang

2017-01-01

This study was conducted to investigate the physicochemical properties of meat batters prepared with fresh pork meat, back fat, water, and salt and formulated with three different amounts (5%, 10%, and 15%) of silkworm pupae (Bombyx mori) powder and transglutaminase (TG). Meat batters formulated with silkworm pupae powder showed significantly higher contents of protein and ash than control batter. Addition of silkworm pupae to batter also showed significantly lower cooking loss than the control. Moreover, meat batter containing 15% silkworm pupae showed no significant difference in redness value compared to the control. In addition, pH, viscosity, hardness, gumminess, and chewiness were improved after the addition of silkworm pupae. Furthermore, meat batter formulated with TG and silkworm pupae showed improved hardness, gumminess, chewiness and viscosity compared to control batter. Addition of 1% TG with 15% silkworm pupae to meat batter resulted in significantly higher pH, textures, and viscosity. Our data suggest that both silkworm pupae and TG can be added to meat batter to improve its physicochemical properties. Therefore, combination of silkworm pupae and TG could be a new nutritional and functional source for meat products. PMID:28747820

Physicochemical Properties of Meat Batter Added with Edible Silkworm Pupae (Bombyx mori) and Transglutaminase.

Science.gov (United States)

Park, Yoo-Sun; Choi, Yun-Sang; Hwang, Ko-Eun; Kim, Tae-Kyung; Lee, Cheol-Won; Shin, Dong-Min; Han, Sung Gu

2017-01-01

This study was conducted to investigate the physicochemical properties of meat batters prepared with fresh pork meat, back fat, water, and salt and formulated with three different amounts (5%, 10%, and 15%) of silkworm pupae ( Bombyx mori ) powder and transglutaminase (TG). Meat batters formulated with silkworm pupae powder showed significantly higher contents of protein and ash than control batter. Addition of silkworm pupae to batter also showed significantly lower cooking loss than the control. Moreover, meat batter containing 15% silkworm pupae showed no significant difference in redness value compared to the control. In addition, pH, viscosity, hardness, gumminess, and chewiness were improved after the addition of silkworm pupae. Furthermore, meat batter formulated with TG and silkworm pupae showed improved hardness, gumminess, chewiness and viscosity compared to control batter. Addition of 1% TG with 15% silkworm pupae to meat batter resulted in significantly higher pH, textures, and viscosity. Our data suggest that both silkworm pupae and TG can be added to meat batter to improve its physicochemical properties. Therefore, combination of silkworm pupae and TG could be a new nutritional and functional source for meat products.

Skin barrier disruption by sodium lauryl sulfate-exposure alters the expressions of involucrin, transglutaminase 1, profilaggrin, and kallikreins during the repair phase in human skin in vivo.

Science.gov (United States)

Törmä, Hans; Lindberg, Magnus; Berne, Berit

2008-05-01

Detergents are skin irritants affecting keratinocytes. In this study, healthy volunteers were exposed to water (vehicle) and 1% sodium lauryl sulfate (SLS) under occlusive patch tests for 24 hours. The messenger RNA (mRNA) expression of keratinocyte differentiation markers and of enzymes involved in corneodesmosome degradation was examined in skin biopsies (n=8) during the repair phase (6 hours to 7 days postexposure) using real-time reverse-transcription PCR. It was found that the expression of involucrin was increased at 6 hours, but then rapidly normalized. The expression of transglutaminase 1 exhibited a twofold increase after 24 hours in the SLS-exposed skin. Profilaggrin was decreased after 6 hours. Later (4-7 days), the expression in SLS-exposed areas was >50% above than in control areas. An increased and altered immunofluorescence pattern of involucrin, transglutaminase 1, and filaggrin was also found (n=4). At 6 hours post-SLS exposure, the mRNA expression of kallikrein-7 (KLK-7) and kallikrein-5 (KLK-5) was decreased by 50 and 75%, respectively, as compared with control and water-exposed areas. Thereafter, the expression pattern of KLK-7 and KLK-5 was normalized. Changes in protein expression of KLK-5 were also found. In conclusion, SLS-induced skin barrier defects induce altered mRNA expression of keratinocyte differentiation markers and enzymes degrading corneodesmosomes.

Role of bicarbonate as a pH buffer and electron sink in microbial dechlorination of chloroethenes

Directory of Open Access Journals (Sweden)

Delgado Anca G

2012-09-01

Full Text Available Abstract Background Buffering to achieve pH control is crucial for successful trichloroethene (TCE anaerobic bioremediation. Bicarbonate (HCO3− is the natural buffer in groundwater and the buffer of choice in the laboratory and at contaminated sites undergoing biological treatment with organohalide respiring microorganisms. However, HCO3− also serves as the electron acceptor for hydrogenotrophic methanogens and hydrogenotrophic homoacetogens, two microbial groups competing with organohalide respirers for hydrogen (H2. We studied the effect of HCO3− as a buffering agent and the effect of HCO3−-consuming reactions in a range of concentrations (2.5-30 mM with an initial pH of 7.5 in H2-fed TCE reductively dechlorinating communities containing Dehalococcoides, hydrogenotrophic methanogens, and hydrogenotrophic homoacetogens. Results Rate differences in TCE dechlorination were observed as a result of added varying HCO3− concentrations due to H2-fed electrons channeled towards methanogenesis and homoacetogenesis and pH increases (up to 8.7 from biological HCO3− consumption. Significantly faster dechlorination rates were noted at all HCO3− concentrations tested when the pH buffering was improved by providing 4-(2-hydroxyethyl-1-piperazineethanesulfonic acid (HEPES as an additional buffer. Electron balances and quantitative PCR revealed that methanogenesis was the main electron sink when the initial HCO3− concentrations were 2.5 and 5 mM, while homoacetogenesis was the dominant process and sink when 10 and 30 mM HCO3− were provided initially. Conclusions Our study reveals that HCO3− is an important variable for bioremediation of chloroethenes as it has a prominent role as an electron acceptor for methanogenesis and homoacetogenesis. It also illustrates the changes in rates and extent of reductive dechlorination resulting from the combined effect of electron donor competition stimulated by HCO3− and the changes in pH exerted by

Endostatin and transglutaminase 2 are involved in fibrosis of the aging kidney.

Science.gov (United States)

Lin, Chi Hua Sarah; Chen, Jun; Zhang, Zhongtao; Johnson, Gail V W; Cooper, Arthur J L; Feola, Julianne; Bank, Alexander; Shein, Jonathan; Ruotsalainen, Heli J; Pihlajaniemi, Taina A; Goligorsky, Michael S

2016-06-01

Endostatin (EST), an antiangiogenic factor, is enriched in aging kidneys. EST is also an interactive partner of transglutaminase 2 (TG2), an enzyme that cross-links extracellular matrix proteins. Here we tested whether EST and TG2 play a role in the fibrosis of aging. In wild-type mice, aging kidneys exhibited a 2- to 4-fold increase in TG2 paralleled by increased cross-linked extracellular matrix proteins and fibrosis. Mice transgenic to express EST showed renal fibrosis at a young age. One-month delivery of EST via minipumps to young mice showed increased renal fibrosis that became more robust when superimposed on folic acid-induced nephropathy. Upregulated TG2 and impaired renal function were apparent with EST delivery combined with folic acid-induced nephropathy. Subcapsular injection of TG2 and/or EST into kidneys of young mice not only induced interstitial fibrosis, but also increased the proportion of senescent cells. Thus, kidney fibrosis in aging may represent a natural outcome of upregulated EST and TG2, but more likely it appears to be a result of cumulative stresses occurring on the background of synergistically acting geronic (aging) proteins, EST and TG2. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Fast microbial reduction of ferrihydrite colloids from a soil effluent

Science.gov (United States)

Fritzsche, Andreas; Bosch, Julian; Rennert, Thilo; Heister, Katja; Braunschweig, Juliane; Meckenstock, Rainer U.; Totsche, Kai U.

2012-01-01

Recent studies on the microbial reduction of synthetic iron oxide colloids showed their superior electron accepting property in comparison to bulk iron oxides. However, natural colloidal iron oxides differ in composition from their synthetic counterparts. Besides a potential effect of colloid size, microbial iron reduction may be accelerated by electron-shuttling dissolved organic matter (DOM) as well as slowed down by inhibitors such as arsenic. We examined the microbial reduction of OM- and arsenic-containing ferrihydrite colloids. Four effluent fractions were collected from a soil column experiment run under water-saturated conditions. Ferrihydrite colloids precipitated from the soil effluent and exhibited stable hydrodynamic diameters ranging from 281 (±146) nm in the effluent fraction that was collected first and 100 (±43) nm in a subsequently obtained effluent fraction. Aliquots of these oxic effluent fractions were added to anoxic low salt medium containing diluted suspensions of Geobacter sulfurreducens. Independent of the initial colloid size, the soil effluent ferrihydrite colloids were quickly and completely reduced. The rates of Fe2+ formation ranged between 1.9 and 3.3 fmol h-1 cell-1, and are in the range of or slightly exceeding previously reported rates of synthetic ferrihydrite colloids (1.3 fmol h-1 cell-1), but greatly exceeding previously known rates of macroaggregate-ferrihydrite reduction (0.07 fmol h-1 cell-1). The inhibition of microbial Fe(III) reduction by arsenic is unlikely or overridden by the concurrent enhancement induced by soil effluent DOM. These organic species may have increased the already high intrinsic reducibility of colloidal ferrihydrite owing to quinone-mediated electron shuttling. Additionally, OM, which is structurally associated with the soil effluent ferrihydrite colloids, may also contribute to the higher reactivity due to increasing solubility and specific surface area of ferrihydrite. In conclusion, ferrihydrite

Evaluating microbial chemical choices: The ocean chemistry basis for the competition between use of O2 or NO3- as an electron acceptor

Science.gov (United States)

Brewer, Peter G.; Hofmann, Andreas F.; Peltzer, Edward T.; Ussler, William, III

2014-05-01

The traditional ocean chemical explanation for the emergence of suboxia is that once O2 levels decline to about 10 μmol kg-1 then onset of NO3- reduction occurs. This piece of ocean chemical lore is well founded in observations and is typically phrased as a microbial choice and not as an obligate requirement. The argument based on O2 levels alone could also be phrased as being dependent on an equivalent amount of NO3- that would yield the same energy gain. This description is based on the availability of the electron acceptor: but the oxidation reactions are usually written out as free energy yield per mole of organic matter, thus not addressing the oxidant availability constraint invoked by ocean scientists. Here we show that the argument can be phrased simply as competing rate processes dependent on the free energy yield ratio per amount of electron acceptor obtained, and thus the [NO3-]:[O2] molar ratio is the critical variable. The rate at which a microbe can acquire either O2 or NO3- to carry out the oxidation reactions is dependent on both the concentration in the bulk ocean, and on the diffusivity within the microbial external molecular boundary layer. From the free energy yield calculations combined with the ~25% greater diffusivity of the O2 molecule we find that the equivalent energy yield occurs at a ratio of about 3.8 NO3-:O2 for a typical Redfield ratio reaction, consistent with an ocean where NO3- reduction onset occurs at about 10 μmol O2:40 μmol NO3-, and the reactions then proceed in parallel along a line of this slope until the next energy barrier is approached. Within highly localized microbial consortia intensely reducing pockets may occur in a bulk ocean containing finite low O2 levels; and the local flux of reduced species from strongly reducing shelf sediments will perturb the large scale water column relationship. But all localized reactions drive towards maximal energy gain from their immediate diffusive surroundings, thus the ocean

Electron Transfer Strategies Regulate Carbonate Mineral and Micropore Formation.

Science.gov (United States)

Zeng, Zhirui; Tice, Michael M

2018-01-01

Some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. However, whether carbonates induced by microbial iron reduction have such features is unknown. Iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). This diversity has the potential to create mineral biosignatures through manipulating the microenvironments in which carbonate precipitation occurs. We used Shewanella oneidensis MR-1, Geothrix fermentans, and Geobacter metallireducens GS-15, representing three different strategies, to reduce solid ferric hydroxide in order to evaluate their influence on carbonate and micropore formation (micro-size porosity in mineral rocks). Our results indicate that electron transfer strategies determined the morphology (rhombohedral, spherical, or long-chained) of precipitated calcium-rich siderite by controlling the level of carbonate saturation and the location of carbonate formation. Remarkably, electron transfer strategies also produced distinctive cell-shaped micropores in both carbonate and hydroxide minerals, thus producing suites of features that could potentially serve as biosignatures recording information about the sizes, shapes, and physiologies of iron-reducing organisms. Key Words: Microbial iron reduction-Micropore-Electron transfer strategies-Microbial carbonate. Astrobiology 18, 28-36.

Electricity production from microbial fuel cell by using yeast

International Nuclear Information System (INIS)

Vorasingha, A.; Souvakon, C.; Boonchom, K.

2006-01-01

The continuous search for methods to generate electricity from renewable sources such as water, solar energy, wind, nuclear or chemicals was discussed with particular focus on attaining the full power of the microbial fuel cell (MFC). Under ideal environmental conditions, the only byproducts of a biofuel cell would be water and carbon dioxide (CO 2 ). The production of energy from renewables such as biomass is important for sustainable development and reducing global emissions of CO 2 . Hydrogen can also be an important component of an energy infrastructure that reduces CO 2 emissions if the hydrogen is produced from renewable sources and used in fuel cells. Hydrogen gas can be biologically produced at high concentration from the fermentation of high sugar substrates such as glucose and sucrose. Some of the issues of MFC design were addressed, including the use of cheap substrates to derive microbial electricity. In the MFC, yeast donates electrons to a chemical electron mediator, which in turn transfers the electrons to an electrode, producing electricity. Experimental results showed that glucose yielded the highest peak voltage, but a semi-processed sugar and molasses were similar to glucose in the electricity production pattern. It was noted that this technology is only at the research stages, and more research is needed before household microbial fuel cells can be made available for producing power for prolonged periods of time. Future research efforts will focus on increasing the efficiency, finding alternatives to hazardous electron mediators and finding new microbes. 12 refs., 6 figs

Enhancement of electricity production by graphene oxide in soil microbial fuel cells and plant microbial fuel cells

Directory of Open Access Journals (Sweden)

Yuko eGoto

2015-04-01

Full Text Available The effects of graphene oxide (GO on electricity generation in soil microbial fuel cells (SMFCs and plant microbial fuel cell (PMFCs were investigated. GO at concentrations ranging from 0 to 1.9 g•kg-1 was added to soil and reduced for 10 days under anaerobic incubation. All SMFCs (GO-SMFCs utilizing the soils incubated with GO produced electricity at a greater rate and in higher quantities than the SMFCs which did not contain GO. In fed-batch operations, the overall average electricity generation in GO-SMFCs containing 1.0 g•kg-1 of GO was 40 ± 19 mW•m-2, which was significantly higher than the value of 6.6 ± 8.9 mW•m-2 generated from GO-free SMFCs (p -2 of electricity after 27 days of operation. Collectively, this study demonstrates that GO added to soil can be microbially reduced in soil, and facilitates electron transfer to the anode in both SMFCs and PMFCs.

Bio-Electron-Fenton (BEF) process driven by microbial fuel cells for triphenyltin chloride (TPTC) degradation

Energy Technology Data Exchange (ETDEWEB)

Yong, Xiao-Yu; Gu, Dong-Yan; Wu, Yuan-Dong [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Yan, Zhi-Ying [Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology, Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041 (China); Zhou, Jun; Wu, Xia-Yuan [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Wei, Ping [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Jia, Hong-Hua [College of Biotechnology and Pharmaceutical Engineering, Nanjing TECH University, Nanjing 211816 (China); Bioenergy Research Institute, Nanjing TECH University, Nanjing 211816 (China); Zheng, Tao, E-mail: zhengtao@ms.giec.ac.cn [Guangzhou Institute of Energy Conversion, Chinese Academy of Science, Nengyuan Road, Guangzhou 510640 (China); Yong, Yang-Chun, E-mail: ycyong@ujs.edu.cn [Biofuels Institute, School of the Environment, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Key Laboratory of Chemical Pollution Control and Resources Reuse, Nanjing University of Science and Technology, Nanjing 210094 (China)

2017-02-15

Graphical abstract: Schematic diagram of the Bio-Electron-Fenton (BEF) process for TPTC degradation. - Highlights: • A Bio-Electro-Fenton process was performed for TPTC degradation. • TPTC removal efficiency achieved 78.32 ± 2.07% within 100 h. • The TPTC degradation rate (0.775 ± 0.021 μmol L{sup −1} h{sup −1}) was much higher than previous reports. - Abstract: The intensive use of triphenyltin chloride (TPTC) has caused serious environmental pollution. In this study, an effective method for TPTC degradation was proposed based on the Bio-Electron-Fenton process in microbial fuel cells (MFCs). The maximum voltage of the MFC with graphite felt as electrode was 278.47% higher than that of carbon cloth. The electricity generated by MFC can be used for in situ generation of H{sub 2}O{sub 2} to a maximum of 135.96 μmol L{sup −1} at the Fe@Fe{sub 2}O{sub 3(*)}/graphite felt composite cathode, which further reacted with leached Fe{sup 2+} to produce hydroxyl radicals. While 100 μmol L{sup −1} TPTC was added to the cathodic chamber, the degradation efficiency of TPTC reached 78.32 ± 2.07%, with a rate of 0.775 ± 0.021 μmol L{sup −1} h{sup −1}. This Bio-Electron-Fenton driving TPTC degradation might involve in Sn−C bonds breaking and the main process is probably a stepwise dephenylation until the formation of inorganic tin and CO{sub 2}. This study provides an energy saving and efficient approach for TPTC degradation.

Microbial diversity in restored wetlands of San Francisco Bay

Energy Technology Data Exchange (ETDEWEB)

Theroux, Susanna [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hartman, Wyatt [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; He, Shaomei [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Univ. of Wisconsin, Madison, WI (United States); Tringe, Susannah [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.

2013-12-09

Wetland ecosystems may serve as either a source or a sink for atmospheric carbon and greenhouse gases. This delicate carbon balance is influenced by the activity of belowground microbial communities that return carbon dioxide and methane to the atmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may help to reverse land subsidence and possibly increase carbon storage in soils. However, the effects of wetland restoration on microbial communities, which mediate soil metabolic activity and carbon cycling, are poorly studied. In an effort to better understand the underlying factors which shape the balance of carbon flux in wetland soils, we targeted the microbial communities in a suite of restored and historic wetlands in the San Francisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhouse gas monitoring, we profiled the diversity and metabolic potential of the wetland soil microbial communities along biogeochemical and wetland age gradients. Our results show relationships among geochemical gradients, availability of electron acceptors, and microbial community composition. Our study provides the first genomic glimpse into microbial populations in natural and restored wetlands of the San Francisco Bay-Delta region and provides a valuable benchmark for future studies.

Electricity production and microbial characterization of thermophilic microbial fuel cells.

Science.gov (United States)

Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

2017-11-01

Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial mineral illization of montmorillonite in low-permeability oil reservoirs for microbial enhanced oil recovery.

Science.gov (United States)

Cui, Kai; Sun, Shanshan; Xiao, Meng; Liu, Tongjing; Xu, Quanshu; Dong, Honghong; Wang, Di; Gong, Yejing; Sha, Te; Hou, Jirui; Zhang, Zhongzhi; Fu, Pengcheng

2018-05-11

Microbial mineral illization has been investigated for its role in the extraction and recovery of metals from ores. Here we report our application of mineral bioillization for the microbial enhanced oil recovery in low-permeability oil reservoirs. It aimed to reveal the etching mechanism of the four Fe (III)-reducing microbial strains under anaerobic growth conditions on the Ca-montmorillonite. The mineralogical characterization of the Ca-montmorillonite was performed by Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy and energy dispersive spectrometer. Results showed that the microbial strains could efficiently reduce Fe (III) at an optimal rate of 71 %, and alter the crystal lattice structure of the lamella to promote the interlayer cation exchange, and to efficiently inhibit the Ca-montmorillonite swelling at an inhibitory rate of 48.9 %. Importance Microbial mineral illization is ubiquitous in the natural environment. Microbes in low-permeability reservoirs are able to enable the alteration of the structure and phase of the Fe-poor minerals by reducing Fe (III) and inhibiting clay swelling which is still poorly studied. This study aimed to reveal the interaction mechanism between Fe (III)-reducing bacterial strains and Ca-montmorillonite under anaerobic atmosphere, and to investigate the extent and rates of Fe (III) reduction and phase changes with their activities. Application of Fe (III)-reducing bacteria will provide a new way to inhibit clay swelling, to elevate reservoir permeability, and to reduce pore throat resistance after water flooding for enhanced oil recovery in low-permeability reservoirs. Copyright © 2018 American Society for Microbiology.

Selenite reduction by anaerobic microbial aggregates: Microbial community structure, and proteins associated to the produced selenium spheres.

Directory of Open Access Journals (Sweden)

Graciela eGonzalez-Gil

2016-04-01

Full Text Available Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0, insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20 % and Pseudomonadaceae (c.a.10 % were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (~200 m of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres

KAUST Repository

Gonzalez-Gil, Graciela

2016-04-26

Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

Microbial O{sub 2} consumption in the Aespoe tunnel

Energy Technology Data Exchange (ETDEWEB)

Kotelnikova, S.; Pedersen, Karsten [Goeteborg Univ. (Sweden). Dept. of Cell and Molecular Biology, Microbiology

1998-04-01

The report presents data on microbial O{sub 2} reduction activities by microorganisms obtained with different techniques: Winkler method, gas chromatography, most probable numbering, enrichment technique, inhibitor analysis and radiotracer measurements. The samples were collected from boreholes and open funnel ponds at Aespoe in 1996-1998. The evaluation of the microbial activities in open ponds predicts the future microbial activities after the O{sub 2} intrusion around the future repository. The metabolic potential of the microbial population inhabiting groundwater was evaluated on the basis of electron donors available and microbial 16S rRNA gene diversity. The contribution of different microbial groups to the O{sub 2} reduction was elucidated using specific inhibitors selectively affecting different microbial groups. Our experiments show that microbial O{sub 2} reduction occurs in deep groundwater. Carbon dioxide was produced concurrently with O{sub 2} reduction confirming the biogenic nature of the reduction. The populations developed O{sub 2} reduction rates and capacity depending on the initial concentration of dissolved O{sub 2} reduction. Rates of O{sub 2} reduction ranged from 0.32 to 4.5 {mu}M/day. Depending on temperature and the type of groundwater the approximate time needed for consumption of 500 {mu}M of dissolved O{sub 2} ranged from 0.31 to 3.99 years. After approximately a 2 weeks period the microbial population in vitro was able to consume O{sub 2} both at 30 deg C and 60 deg C. At 16 deg C no delay in O{sub 2} consumption was observed. Our results demonstrated that methanotrophs survive in deep groundwater and that they were induced by O{sub 2}. Some bacteria use Hg or CH{sub 4} as electron donor instead of organic matter, which means that microbial O{sub 2} reduction will occur also in deep groundwaters where the availability of organic carbon is limited. Specific CH{sub 4} oxidation rates ranged between 3.00 and 220 nM CH{sub 4} per litre per

Regulation of Endothelial Cell Inflammation and Lung PMN Infiltration by Transglutaminase 2

Science.gov (United States)

Bijli, Kaiser M.; Kanter, Bryce G.; Minhajuddin, Mohammad; Leonard, Antony; Xu, Lei; Fazal, Fabeha; Rahman, Arshad

2014-01-01

We addressed the role of transglutaminase2 (TG2), a calcium-dependent enzyme that catalyzes crosslinking of proteins, in the mechanism of endothelial cell (EC) inflammation and lung PMN infiltration. Exposure of EC to thrombin, a procoagulant and proinflammatory mediator, resulted in activation of the transcription factor NF-κB and its target genes, VCAM-1, MCP-1, and IL-6. RNAi knockdown of TG2 inhibited these responses. Analysis of NF-κB activation pathway showed that TG2 knockdown was associated with inhibition of thrombin-induced DNA binding as well as serine phosphorylation of RelA/p65, a crucial event that controls transcriptional capacity of the DNA-bound RelA/p65. These results implicate an important role for TG2 in mediating EC inflammation by promoting DNA binding and transcriptional activity of RelA/p65. Because thrombin is released in high amounts during sepsis and its concentration is elevated in plasma and lavage fluids of patients with Acute Respiratory Distress Syndrome (ARDS), we determined the in vivo relevance of TG2 in a mouse model of sepsis-induced lung PMN recruitment. A marked reduction in NF-κB activation, adhesion molecule expression, and lung PMN sequestration was observed in TG2 knockout mice compared to wild type mice exposed to endotoxemia. Together, these results identify TG2 as an important mediator of EC inflammation and lung PMN sequestration associated with intravascular coagulation and sepsis. PMID:25057925

Microbial Electrochemistry and its Application to Energy and Environmental Issues

Science.gov (United States)

Hastings, Jason Thomas

Microbial electrochemistry forms the basis of a wide range of topics from microbial fuel cells to fermentation of carbon food sources. The ability to harness microbial electron transfer processes can lead to a greener and cleaner future. This study focuses on microbial electron transfer for liquid fuel production, novel electrode materials, subsurface environments and removal of unwanted byproducts. In the first chapter, exocellular electron transfer through direct contact utilizing passive electrodes for the enhancement of bio-fuel production was tested. Through the application of microbial growth in a 2-cell apparatus on an electrode surface ethanol production was enhanced by 22.7% over traditional fermentation. Ethanol production efficiencies of close to 95% were achieved in a fraction of the time required by traditional fermentation. Also, in this chapter, the effect of exogenous electron shuttles, electrode material selection and resistance was investigated. Power generation was observed using the 2-cell passive electrode system. An encapsulation method, which would also utilize exocellular transfer of electrons through direct contact, was hypothesized for the suspension of viable cells in a conductive polymer substrate. This conductive polymer substrate could have applications in bio-fuel production. Carbon black was added to a polymer solution to test electrospun polymer conductivity and cell viability. Polymer morphology and cell viability were imaged using electron and optical microscopy. Through proper encapsulation, higher fuel production efficiencies would be achievable. Electron transfer through endogenous exocellular protein shuttles was observed in this study. Secretion of a soluble redox active exocellular protein by Clostridium sp. have been shown utilizing a 2-cell apparatus. Cyclic voltammetry and gel electrophoresis were used to show the presence of the protein. The exocellular protein is capable of reducing ferrous iron in a membrane separated

Tissue transglutaminase (TG-2) modified amniotic membrane: a novel scaffold for biomedical applications

International Nuclear Information System (INIS)

Chau, David Y S; Brown, Sheridan V; Ghaemmaghami, Amir M; Mather, Melissa L; Hutter, Victoria; Tint, Naing L; Rose, Felicity R A J; Dua, Harminder S

2012-01-01

The amniotic membrane (AM) is considered as a natural cell culture substrate and has occasionally been exploited in regenerative medicine especially for ocular surface reconstruction and dermal wound healing applications. However, its use is limited by its relatively weak mechanical strength, difficulty during manual handling and susceptibility to proteolytic degradation in vivo. Therefore, in this study we aimed to enhance the mechanical and biological characteristics of the AM by enzymatically cross-linking it using tissue transglutaminase (TG)—a calcium-dependent enzyme capable of forming stable ε(γ-glutamyl)lysine cross-linkages. Using a biological catalyst such as TG does not only prevent denaturation during sample preparation but also minimizes the potential of residual chemical cross-linking agents compared to alternative methodologies. Human AM, sourced from elective caesarean sectioning, were treated with TG, bovine serum albumin and/or a no-treatment control. Samples were then compared in terms of their physical and (scanning electron microscopy (SEM), transparency, mechanical strength, susceptibility to proteolytic degradation) biological characteristics (in vitro cell culture, activation of dendritic cells (DC)) and their in vivo biocompatibility/angiogenic capacity (chick chorioallantoic membrane assay). TG-treated AM exhibited enhanced mechanical strength and greater resistance to proteolytic/collagenase degradation compared to the control(s). SEM imaging of the TG-treated membrane summarized a significantly closer association and greater interconnectivity of individual collagen fibres yet it had no effect on the overall transparency of the AM. In vitro cell culture demonstrated no detrimental effect of TG-treatment on the AM in terms of cell attachment, spreading, proliferation and differentiation. Moreover, an ‘immune response’ was not elicited based on extended in vitro culture with human-monocyte-derived DC. Interestingly, the TG

Environmental controls on microbial communities in continental serpentinite fluids

Directory of Open Access Journals (Sweden)

Melitza eCrespo-Medina

2014-11-01

Full Text Available Geochemical reactions associated with serpentinization alter the composition of dissolved organic compounds in circulating fluids and potentially liberate mantle-derived carbon and reducing power to support subsurface microbial communities. Previous studies have identified Betaproteobacteria from the order Burkholderiales and bacteria from the order Clostridiales as key components of the serpentinite–hosted microbiome, however there is limited knowledge of their metabolic capabilities or growth characteristics. In an effort to better characterize microbial communities, their metabolism, and factors limiting their activities, microcosm experiments were designed with fluids collected from several monitoring wells at the Coast Range Ophiolite Microbial Observatory (CROMO in northern California during expeditions in March and August 2013. The incubations were initiated with a hydrogen atmosphere and a variety of carbon sources (carbon dioxide, methane, acetate and formate, with and without the addition of nutrients and electron acceptors. Growth was monitored by direct microscopic counts; DNA yield and community composition was assessed at the end of the three month incubation. For the most part, results indicate that bacterial growth was favored by the addition of acetate and methane, and that the addition of nutrients and electron acceptors had no significant effect on microbial growth, suggesting no nutrient- or oxidant-limitation. However the addition of sulfur amendments led to different community compositions. The dominant organisms at the end of the incubations were closely related to Dethiobacter sp. and to the family Comamonadaceae, which are also prominent in culture-independent gene sequencing surveys. These experiments provide one of first insights into the biogeochemical dynamics of the serpentinite subsurface environment and will facilitate experiments to trace microbial activities in serpentinizing ecosystems.

Enterobacter siamensis sp. nov., a transglutaminase-producing bacterium isolated from seafood processing wastewater in Thailand.

Science.gov (United States)

Khunthongpan, Suwannee; Bourneow, Chaiwut; H-Kittikun, Aran; Tanasupawat, Somboon; Benjakul, Soottawat; Sumpavapol, Punnanee

2013-01-01

A novel strain of Enterobacter, C2361(T), a Gram-negative, non-spore-forming, rod-shaped and facultative anaerobic bacterium with the capability to produce transglutaminase, was isolated from seafood processing wastewater collected from a treatment pond of a seafood factory in Songkhla Province, Thailand. Phylogenetic analyses and phenotypic characteristics, including chemotaxonomic characteristics, showed that the strain was a member of the genus Enterobacter. The 16S rRNA gene sequence similarities between strain C2361(T) and Enterobacter cloacae subsp. cloacae ATCC 13047(T) and Enterobacter cloacae subsp. dissolvens LMG 2683(T) were 97.5 and 97.5%, respectively. Strain C2361(T) showed a low DNA-DNA relatedness with the above-mentioned species. The major fatty acids were C16:0, C17:0cyclo and C14:0. The DNA G+C content was 53.0 mol%. On the basis of the polyphasic evidence gathered in this study, it should be classified as a novel species of the genus Enterobacter for which the name Enterobacter siamensis sp. nov. is proposed. The type strain is C2361(T) (= KCTC 23282(T) = NBRC 107138(T)).

Tissue Transglutaminase (TG2)-Induced Inflammation in Initiation, Progression, and Pathogenesis of Pancreatic Cancer

Energy Technology Data Exchange (ETDEWEB)

Mehta, Kapil, E-mail: kmehta@mdanderson.org; Han, Amy [Department of Experimental Therapeutics, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030 (United States); Graduate School of Biomedical Sciences, The University of Texas Health Science Center, Houston, TX 77030 (United States)

2011-02-25

Pancreatic cancer (PC) is among the deadliest cancers, with a median survival of six months. It is generally believed that infiltrating PC arises through the progression of early grade pancreatic intraepithelial lesions (PanINs). In one model of the disease, the K-ras mutation is an early molecular event during progression of pancreatic cancer; it is followed by the accumulation of additional genetic abnormalities. This model has been supported by animal studies in which activated K-ras and p53 mutations produced metastatic pancreatic ductal adenocarcinoma in mice. According to this model, oncogenic K-ras induces PanIN formation but fails to promote the invasive stage. However, when these mice are subjected to caerulein treatment, which induces a chronic pancreatitis-like state and inflammatory response, PanINs rapidly progress to invasive carcinoma. These results are consistent with epidemiologic studies showing that patients with chronic pancreatitis have a much higher risk of developing PC. In line with these observations, recent studies have revealed elevated expression of the pro-inflammatory protein tissue transglutaminase (TG2) in early PanINs, and its expression increases even more as the disease progresses. In this review we discuss the implications of increased TG2 expression in initiation, progression, and pathogenesis of pancreatic cancer.

A1 adenosine receptor-induced phosphorylation and modulation of transglutaminase 2 activity in H9c2 cells: A role in cell survival.

Science.gov (United States)

Vyas, Falguni S; Hargreaves, Alan J; Bonner, Philip L R; Boocock, David J; Coveney, Clare; Dickenson, John M

2016-05-01

The regulation of tissue transglutaminase (TG2) activity by the GPCR family is poorly understood. In this study, we investigated the modulation of TG2 activity by the A1 adenosine receptor in cardiomyocyte-like H9c2 cells. H9c2 cells were lysed following stimulation with the A1 adenosine receptor agonist N(6)-cyclopentyladenosine (CPA). Transglutaminase activity was determined using an amine incorporating and a protein cross linking assay. TG2 phosphorylation was assessed via immunoprecipitation and Western blotting. The role of TG2 in A1 adenosine receptor-induced cytoprotection was investigated by monitoring hypoxia-induced cell death. CPA induced time and concentration-dependent increases in amine incorporating and protein crosslinking activity of TG2. CPA-induced increases in TG2 activity were attenuated by the TG2 inhibitors Z-DON and R283. Responses to CPA were blocked by PKC (Ro 31-8220), MEK1/2 (PD 98059), p38 MAPK (SB 203580) and JNK1/2 (SP 600125) inhibitors and by removal of extracellular Ca(2+). CPA triggered robust increases in the levels of TG2-associated phosphoserine and phosphothreonine, which were attenuated by PKC, MEK1/2 and JNK1/2 inhibitors. Fluorescence microscopy revealed TG2-mediated biotin-X-cadaverine incorporation into proteins and proteomic analysis identified known (Histone H4) and novel (Hexokinase 1) protein substrates for TG2. CPA pre-treatment reversed hypoxia-induced LDH release and decreases in MTT reduction. TG2 inhibitors R283 and Z-DON attenuated A1 adenosine receptor-induced cytoprotection. TG2 activity was stimulated by the A1 adenosine receptor in H9c2 cells via a multi protein kinase dependent pathway. These results suggest a role for TG2 in A1 adenosine receptor-induced cytoprotection. Copyright © 2016 Elsevier Inc. All rights reserved.

Hadal biosphere: insight into the microbial ecosystem in the deepest ocean on Earth.

Science.gov (United States)

Nunoura, Takuro; Takaki, Yoshihiro; Hirai, Miho; Shimamura, Shigeru; Makabe, Akiko; Koide, Osamu; Kikuchi, Tohru; Miyazaki, Junichi; Koba, Keisuke; Yoshida, Naohiro; Sunamura, Michinari; Takai, Ken

2015-03-17

Hadal oceans at water depths below 6,000 m are the least-explored aquatic biosphere. The Challenger Deep, located in the western equatorial Pacific, with a water depth of ∼11 km, is the deepest ocean on Earth. Microbial communities associated with waters from the sea surface to the trench bottom (0∼10,257 m) in the Challenger Deep were analyzed, and unprecedented trench microbial communities were identified in the hadal waters (6,000∼10,257 m) that were distinct from the abyssal microbial communities. The potentially chemolithotrophic populations were less abundant in the hadal water than those in the upper abyssal waters. The emerging members of chemolithotrophic nitrifiers in the hadal water that likely adapt to the higher flux of electron donors were also different from those in the abyssal waters that adapt to the lower flux of electron donors. Species-level niche separation in most of the dominant taxa was also found between the hadal and abyssal microbial communities. Considering the geomorphology and the isolated hydrotopographical nature of the Mariana Trench, we hypothesized that the distinct hadal microbial ecosystem was driven by the endogenous recycling of organic matter in the hadal waters associated with the trench geomorphology.

Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

Science.gov (United States)

Graw, Michael F.; D'Angelo, Grace; Borchers, Matthew; Thurber, Andrew R.; Johnson, Joel E.; Zhang, Chuanlun; Liu, Haodong; Colwell, Frederick S.

2018-01-01

The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS) experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP) at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics. PMID:29696012

Quantitative analysis of microbial biomass yield in aerobic bioreactor.

Science.gov (United States)

Watanabe, Osamu; Isoda, Satoru

2013-12-01

We have studied the integrated model of reaction rate equations with thermal energy balance in aerobic bioreactor for food waste decomposition and showed that the integrated model has the capability both of monitoring microbial activity in real time and of analyzing biodegradation kinetics and thermal-hydrodynamic properties. On the other hand, concerning microbial metabolism, it was known that balancing catabolic reactions with anabolic reactions in terms of energy and electron flow provides stoichiometric metabolic reactions and enables the estimation of microbial biomass yield (stoichiometric reaction model). We have studied a method for estimating real-time microbial biomass yield in the bioreactor during food waste decomposition by combining the integrated model with the stoichiometric reaction model. As a result, it was found that the time course of microbial biomass yield in the bioreactor during decomposition can be evaluated using the operational data of the bioreactor (weight of input food waste and bed temperature) by the combined model. The combined model can be applied to manage a food waste decomposition not only for controlling system operation to keep microbial activity stable, but also for producing value-added products such as compost on optimum condition. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Characterizing microbial diversity and damage in mural paintings.

Science.gov (United States)

Rosado, Tânia; Mirão, José; Candeias, António; Caldeira, Ana Teresa

2015-02-01

Mural paintings are some of the oldest and most important cultural expressions of mankind and play an important role for the understanding of societies and civilizations. These cultural assets have high economic and cultural value and therefore their degradation has social and economic impact. The present work presents a novel microanalytical approach to understand the damages caused by microbial communities in mural paintings. This comprises the characterization and identification of microbial diversity and evaluation of damage promoted by their biological activity. Culture-dependent methods and DNA-based approaches like denaturing gradient gel electrophoresis (DGGE) and pyrosequencing are important tools in the isolation and identification of the microbial communities allowing characterization of the biota involved in the biodeterioration phenomena. Raman microspectrometry, infrared spectrometry, and variable pressure scanning electron microscopy coupled with energy-dispersive X-ray spectrometry are also useful tools for evaluation of the presence of microbial contamination and detection of the alteration products resulting from metabolic activity of the microorganisms. This study shows that the degradation status of mural paintings can be correlated to the presence of metabolically active microorganisms.

Microbial biomass carbon and enzyme activities of urban soils in Beijing.

Science.gov (United States)

Wang, Meie; Markert, Bernd; Shen, Wenming; Chen, Weiping; Peng, Chi; Ouyang, Zhiyun

2011-07-01

To promote rational and sustainable use of soil resources and to maintain the urban soil quality, it is essential to assess urban ecosystem health. In this study, the microbiological properties of urban soils in Beijing and their spatial distribution patterns across the city were evaluated based on measurements of microbial biomass carbon and urease and invertase activities of the soils for the purpose of assessing the urban ecosystem health of Beijing. Grid sampling design, normal Kriging technique, and the multiple comparisons among different land use types were used in soil sampling and data treatment. The inherent chemical characteristics of urban soils in Beijing, e.g., soil pH, electronic conductivity, heavy metal contents, total N, P and K contents, and soil organic matter contents were detected. The size and diversity of microbial community and the extent of microbial activity in Beijing urban soils were measured as the microbial biomass carbon content and the ratio of microbial biomass carbon content to total soil organic carbon. The microbial community health measured in terms of microbial biomass carbon, urease, and invertase activities varied with the organic substrate and nutrient contents of the soils and were not adversely affected by the presence of heavy metals at p urban soils influenced the nature and activities of the microbial communities.

Solar energy powered microbial fuel cell with a reversible bioelectrode.

Science.gov (United States)

Strik, David P B T B; Hamelers, Hubertus V M; Buisman, Cees J N

2010-01-01

The solar energy powered microbial fuel cell is an emerging technology for electricity generation via electrochemically active microorganisms fueled by solar energy via in situ photosynthesized metabolites from algae, cyanobacteria, or living higher plants. A general problem with microbial fuel cells is the pH membrane gradient which reduces cell voltage and power output. This problem is caused by acid production at the anode, alkaline production at the cathode, and the nonspecific proton exchange through the membrane. Here we report a solution for a new kind of solar energy powered microbial fuel cell via development of a reversible bioelectrode responsible for both biocatalyzed anodic and cathodic electron transfer. Anodic produced protons were used for the cathodic reduction reaction which held the formation of a pH membrane gradient. The microbial fuel cell continuously generated electricity and repeatedly reversed polarity dependent on aeration or solar energy exposure. Identified organisms within biocatalyzing biofilm of the reversible bioelectrode were algae, (cyano)bacteria and protozoa. These results encourage application of solar energy powered microbial fuel cells.

Recent advances in electronic nose techniques for monitoring of fermentation process.

Science.gov (United States)

Jiang, Hui; Zhang, Hang; Chen, Quansheng; Mei, Congli; Liu, Guohai

2015-12-01

Microbial fermentation process is often sensitive to even slight changes of conditions that may result in unacceptable end-product quality. Thus, the monitoring of the process is critical for discovering unfavorable deviations as early as possible and taking the appropriate measures. However, the use of traditional analytical techniques is often time-consuming and labor-intensive. In this sense, the most effective way of developing rapid, accurate and relatively economical method for quality assurance in microbial fermentation process is the use of novel chemical sensor systems. Electronic nose techniques have particular advantages in non-invasive monitoring of microbial fermentation process. Therefore, in this review, we present an overview of the most important contributions dealing with the quality control in microbial fermentation process using the electronic nose techniques. After a brief description of the fundamentals of the sensor techniques, some examples of potential applications of electronic nose techniques monitoring are provided, including the implementation of control strategies and the combination with other monitoring tools (i.e. sensor fusion). Finally, on the basis of the review, the electronic nose techniques are critically commented, and its strengths and weaknesses being highlighted. In addition, on the basis of the observed trends, we also propose the technical challenges and future outlook for the electronic nose techniques.

Geobacter sulfurreducens adapts to low electrode potential for extracellular electron transfer

International Nuclear Information System (INIS)

Peng, Luo; Zhang, Xiao-Ting; Yin, Jie; Xu, Shuo-Yuan; Zhang, Yong; Xie, De-Ti; Li, Zhen-Lun

2016-01-01

Microbial extracellular electron transfer (EET) occurring in natural and engineering processes is attracting increasing interests. While a meaningful question for bioenergetics, microbial physiology and microbial electrochemical systems; less is known about the lower limit of electron acceptor reduction potential for EET. It is also unclear how microbes adapt to weak electron acceptors. This study evaluated Geobacter sulfurreducens biofilms grown with an electrode poised at −0.25 V vs. SHE. This potential was found to be sufficient for microbial metabolism and proliferation. The turnover cyclic voltammetries found that these biofilms had a half-saturation potential of −0.242 ± 0.004 V, in contrast to −0.151 ± 0.003 V for that of the biofilms grown under 0.2 V. For the biofilms grown under 0.2 V, differential pulse voltammetry showed that the metabolic current was mediated by interfacial cofactors with mid-point potential around −0.16 V performing single-electron electron transfer (ET). The major electron conduits for the biofilms respiring under −0.25 V had mid-point potentials of −0.22 V or −0.26 V, which appeared to perform two-electron ET. Under the non-turnover condition, both biofilms showed similar patterns in voltammograms and the low-potential conduits largely disappeared for the biofilms grown under −0.25 V. Transcriptome analysis identified 17 cytochrome-c genes significantly up-regulated for the biofilms grown under −0.25 V, together with many other genes linked to the ET system. It was also noted that, lowering the poised potential from −0.25 V to −0.28 V (the fuel standard oxidation potential) did not fully inhibit microbial respiration.

Stimulating soil microorganisms for mineralizing the herbicide isoproturon by means of microbial electroremediating cells.

Science.gov (United States)

Rodrigo Quejigo, Jose; Dörfler, Ulrike; Schroll, Reiner; Esteve-Núñez, Abraham

2016-05-01

The absence of suitable terminal electron acceptors (TEA) in soil might limit the oxidative metabolism of environmental microbial populations. Microbial electroremediating cells (MERCs) consist in a variety of bioelectrochemical devices that aim to overcome electron acceptor limitation and maximize metabolic oxidation with the purpose of enhancing the biodegradation of a pollutant in the environment. The objective of this work was to use MERCs principles for stimulating soil bacteria to achieve the complete biodegradation of the herbicide (14) C-isoproturon (IPU) to (14) CO(2) in soils. Our study concludes that using electrodes at a positive potential [+600 mV (versus Ag/AgCl)] enhanced the mineralization by 20-fold respect the electrode-free control. We also report an overall profile of the (14) C-IPU metabolites and a (14) C mass balance in response to the different treatments. The remarkable impact of electrodes on the microbial activity of natural communities suggests a promising future for this emerging environmental technology that we propose to name bioelectroventing. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Ferrihydrite-associated organic matter (OM stimulates reduction by Shewanella oneidensis MR-1 and a complex microbial consortia

Directory of Open Access Journals (Sweden)

R. E. Cooper

2017-11-01

Full Text Available The formation of Fe(III oxides in natural environments occurs in the presence of natural organic matter (OM, resulting in the formation of OM–mineral complexes that form through adsorption or coprecipitation processes. Thus, microbial Fe(III reduction in natural environments most often occurs in the presence of OM–mineral complexes rather than pure Fe(III minerals. This study investigated to what extent does the content of adsorbed or coprecipitated OM on ferrihydrite influence the rate of Fe(III reduction by Shewanella oneidensis MR-1, a model Fe(III-reducing microorganism, in comparison to a microbial consortium extracted from the acidic, Fe-rich Schlöppnerbrunnen fen. We found that increased OM content led to increased rates of microbial Fe(III reduction by S. oneidensis MR-1 in contrast to earlier findings with the model organism Geobacter bremensis. Ferrihydrite–OM coprecipitates were reduced slightly faster than ferrihydrites with adsorbed OM. Surprisingly, the complex microbial consortia stimulated by a mixture of electrons donors (lactate, acetate, and glucose mimics S. oneidensis under the same experimental Fe(III-reducing conditions suggesting similar mechanisms of electron transfer whether or not the OM is adsorbed or coprecipitated to the mineral surfaces. We also followed potential shifts of the microbial community during the incubation via 16S rRNA gene sequence analyses to determine variations due to the presence of adsorbed or coprecipitated OM–ferrihydrite complexes in contrast to pure ferrihydrite. Community profile analyses showed no enrichment of typical model Fe(III-reducing bacteria, such as Shewanella or Geobacter sp., but an enrichment of fermenters (e.g., Enterobacteria during pure ferrihydrite incubations which are known to use Fe(III as an electron sink. Instead, OM–mineral complexes favored the enrichment of microbes including Desulfobacteria and Pelosinus sp., both of which can utilize lactate and

Ferrihydrite-associated organic matter (OM) stimulates reduction by Shewanella oneidensis MR-1 and a complex microbial consortia

Science.gov (United States)

Cooper, Rebecca Elizabeth; Eusterhues, Karin; Wegner, Carl-Eric; Totsche, Kai Uwe; Küsel, Kirsten

2017-11-01

The formation of Fe(III) oxides in natural environments occurs in the presence of natural organic matter (OM), resulting in the formation of OM-mineral complexes that form through adsorption or coprecipitation processes. Thus, microbial Fe(III) reduction in natural environments most often occurs in the presence of OM-mineral complexes rather than pure Fe(III) minerals. This study investigated to what extent does the content of adsorbed or coprecipitated OM on ferrihydrite influence the rate of Fe(III) reduction by Shewanella oneidensis MR-1, a model Fe(III)-reducing microorganism, in comparison to a microbial consortium extracted from the acidic, Fe-rich Schlöppnerbrunnen fen. We found that increased OM content led to increased rates of microbial Fe(III) reduction by S. oneidensis MR-1 in contrast to earlier findings with the model organism Geobacter bremensis. Ferrihydrite-OM coprecipitates were reduced slightly faster than ferrihydrites with adsorbed OM. Surprisingly, the complex microbial consortia stimulated by a mixture of electrons donors (lactate, acetate, and glucose) mimics S. oneidensis under the same experimental Fe(III)-reducing conditions suggesting similar mechanisms of electron transfer whether or not the OM is adsorbed or coprecipitated to the mineral surfaces. We also followed potential shifts of the microbial community during the incubation via 16S rRNA gene sequence analyses to determine variations due to the presence of adsorbed or coprecipitated OM-ferrihydrite complexes in contrast to pure ferrihydrite. Community profile analyses showed no enrichment of typical model Fe(III)-reducing bacteria, such as Shewanella or Geobacter sp., but an enrichment of fermenters (e.g., Enterobacteria) during pure ferrihydrite incubations which are known to use Fe(III) as an electron sink. Instead, OM-mineral complexes favored the enrichment of microbes including Desulfobacteria and Pelosinus sp., both of which can utilize lactate and acetate as an electron

Anti-microbial antibodies in celiac disease: Trick or treat?

Science.gov (United States)

Papp, Maria; Foldi, Ildiko; Altorjay, Istvan; Palyu, Eszter; Udvardy, Miklos; Tumpek, Judit; Sipka, Sandor; Korponay-Szabo, Ilma Rita; Nemes, Eva; Veres, Gabor; Dinya, Tamas; Tordai, Attila; Andrikovics, Hajnalka; Norman, Gary L; Lakatos, Peter Laszlo

2009-01-01

AIM: To determine the prevalence of a new set of anti-glycan and anti-outer membrane protein (anti-OMP) antibodies in a Hungarian cohort of adult Celiac disease (CD) patients. METHODS: 190 consecutive CD patients [M/F: 71/119, age:39.9 (SD:14.1) years], 100 healthy, and 48 gastrointestinal controls were tested for glycan anti-Saccharomyces cerevisiae (gASCA), anti-laminaribioside (ALCA), anti-chitobioside, anti-mannobioside, anti-OMP antibodies and major NOD2/CARD15 mutations. Thirty out of 82 CD patients enrolled at the time of diagnosis were re-evaluated for the same antibodies after longstanding gluten-free diet (GFD). RESULTS: 65.9% of the CD patients were positive for at least one of the tested antibodies at the time of the diagnosis. Except anti-OMP and ALCA, anti-microbial antibodies were exclusively seen in untreated CD; however, the overall sensitivity was low. Any glycan positivity (LR+: 3.13; 95% CI: 2.08-4.73) was associated with an increased likelihood ratio for diagnosing CD. Significant correlation was found between the levels of anti-glycan and anti-endomysial or anti-transglutaminase antibodies. Anti-glycan positivity was lost after longstanding GFD. Anti-glycan antibody titers were associated with symptoms at presentation, but not the presence of NOD2/CARD15 mutations. Patients with severe malabsorption more frequently had multiple antibodies at diagnosis (P = 0.019). CONCLUSION: The presence of anti-glycan antibodies in CD seems to be secondary to the impaired small bowel mucosa which can lead to increased antigen presentation. Furthermore, anti-glycan positivity may be considered an additional marker of CD and dietary adherence. PMID:19701969

Energy, ecology and the distribution of microbial life.

Science.gov (United States)

Macalady, Jennifer L; Hamilton, Trinity L; Grettenberger, Christen L; Jones, Daniel S; Tsao, Leah E; Burgos, William D

2013-07-19

Mechanisms that govern the coexistence of multiple biological species have been studied intensively by ecologists since the turn of the nineteenth century. Microbial ecologists in the meantime have faced many fundamental challenges, such as the lack of an ecologically coherent species definition, lack of adequate methods for evaluating population sizes and community composition in nature, and enormous taxonomic and functional diversity. The accessibility of powerful, culture-independent molecular microbiology methods offers an opportunity to close the gap between microbial science and the main stream of ecological theory, with the promise of new insights and tools needed to meet the grand challenges humans face as planetary engineers and galactic explorers. We focus specifically on resources related to energy metabolism because of their direct links to elemental cycling in the Earth's history, engineering applications and astrobiology. To what extent does the availability of energy resources structure microbial communities in nature? Our recent work on sulfur- and iron-oxidizing autotrophs suggests that apparently subtle variations in the concentration ratios of external electron donors and acceptors select for different microbial populations. We show that quantitative knowledge of microbial energy niches (population-specific patterns of energy resource use) can be used to predict variations in the abundance of specific taxa in microbial communities. Furthermore, we propose that resource ratio theory applied to micro-organisms will provide a useful framework for identifying how environmental communities are organized in space and time.

Continuous power generation and microbial community structure of the anode biofilms in a three-stage microbial fuel cell system

Energy Technology Data Exchange (ETDEWEB)

Chung, Kyungmi; Okabe, Satoshi [Hokkaido Univ., Sapporo (Japan). Dept. of Urban and Environmental Engineering

2009-07-15

A mediator-less three-stage two-chamber microbial fuel cell (MFC) system was developed and operated continuously for more than 1.5 years to evaluate continuous power generation while treating artificial wastewater containing glucose (10 mM) concurrently. A stable power density of 28 W/m3 was attained with an anode hydraulic retention time of 4.5 h and phosphate buffer as the cathode electrolyte. An overall dissolved organic carbon removal ratio was about 85%, and coulombic efficiency was about 46% in this MFC system. We also analyzed the microbial community structure of anode biofilms in each MFC. Since the environment in each MFC was different due to passing on the products to the next MFC in series, the microbial community structure was different accordingly. The anode biofilm in the first MFC consisted mainly of bacteria belonging to the Gammaproteobacteria, identified as Aeromonas sp., while the Firmicutes dominated the anode biofilms in the second and third MFCs that were mainly fed with acetate. Cyclic voltammetric results supported the presence of a redox compound(s) associated with the anode biofilm matrix, rather than mobile (dissolved) forms, which could be responsible for the electron transfer to the anode. Scanning electron microscopy revealed that the anode biofilms were comprised of morphologically different cells that were firmly attached on the anode surface and interconnected each other with anchor-like filamentous appendages, which might support the results of cyclic voltammetry. (orig.)

Energy Gradients Structure Microbial Communities Across Sediment Horizons in Deep Marine Sediments of the South China Sea

Directory of Open Access Journals (Sweden)

Michael F. Graw

2018-04-01

Full Text Available The deep marine subsurface is a heterogeneous environment in which the assembly of microbial communities is thought to be controlled by a combination of organic matter deposition, electron acceptor availability, and sedimentology. However, the relative importance of these factors in structuring microbial communities in marine sediments remains unclear. The South China Sea (SCS experiences significant variability in sedimentation across the basin and features discrete changes in sedimentology as a result of episodic deposition of turbidites and volcanic ashes within lithogenic clays and siliceous or calcareous ooze deposits throughout the basin's history. Deep subsurface microbial communities were recently sampled by the International Ocean Discovery Program (IODP at three locations in the SCS with sedimentation rates of 5, 12, and 20 cm per thousand years. Here, we used Illumina sequencing of the 16S ribosomal RNA gene to characterize deep subsurface microbial communities from distinct sediment types at these sites. Communities across all sites were dominated by several poorly characterized taxa implicated in organic matter degradation, including Atribacteria, Dehalococcoidia, and Aerophobetes. Sulfate-reducing bacteria comprised only 4% of the community across sulfate-bearing sediments from multiple cores and did not change in abundance in sediments from the methanogenic zone at the site with the lowest sedimentation rate. Microbial communities were significantly structured by sediment age and the availability of sulfate as an electron acceptor in pore waters. However, microbial communities demonstrated no partitioning based on the sediment type they inhabited. These results indicate that microbial communities in the SCS are structured by the availability of electron donors and acceptors rather than sedimentological characteristics.

Transglutaminase 2 expression in acute myeloid leukemia: Association with adhesion molecule expression and leukemic blast motility

Science.gov (United States)

Meyer, Stefan; Ravandi-Kashani, Farhad; Borthakur, Gautam; Coombes, Kevin R.; Zhang, Nianxiang; Kornblau, Steven

2016-01-01

Acute myeloid leukemia (AML) is a heterogenous disease with differential oncogene association, outcome and treatment regimens. Treatment strategies for AML have improved outcome but despite increased molecular biological information AML is still associated with poor prognosis. Proteomic analysis on the effects of a range of leukemogenic oncogenes showed that the protein transglutaminase 2 (TG2) is expressed at greater levels as a consequence of oncogenic transformation. Further analysis of this observation was performed with 511 AML samples using reverse phase proteomic arrays, demonstrating that TG2 expression was higher at relapse than diagnosis in many cases. In addition elevated TG2 expression correlated with increased expression of numerous adhesion proteins and many apoptosis regulating proteins, two processes related to leukemogenesis. TG2 has previously been linked to drug resistance in cancer and given the negative correlation between TG2 levels and peripheral blasts observed increased TG2 levels may lead to the protection of the leukemic stem cell due to increased adhesion/reduced motility. TG2 may therefore form part of a network of proteins that define poor outcome in AML patients and potentially offer a target to sensitize AML stem cells to drug treatment. PMID:23576428

Involvement of Transglutaminase-2 in α-MSH-Induced Melanogenesis in SK-MEL-2 Human Melanoma Cells.

Science.gov (United States)

Kim, Hyun Ji; Lee, Hye Ja; Park, Mi Kyung; Gang, Kyung Jin; Byun, Hyun Jung; Park, Jeong Ho; Kim, Mi Kyung; Kim, Soo Youl; Lee, Chang Hoon

2014-05-01

Skin hyperpigmentation is one of the most common skin disorders caused by abnormal melanogenesis. The mechanism and key factors at play are not fully understood. Previous reports have indicated that cystamine (CTM) inhibits melanin synthesis, though its molecular mechanism in melanogenesis remains unclear. In the present study, we investigated the effect of CTM on melanin production using ELISA reader and the expression of proteins involved in melanogenesis by Western blotting, and examined the involvement of transglutaminase-2 (Tgase-2) in SK-MEL-2 human melanoma cells by gene silencing. In the results, CTM dose-dependently suppressed melanin production and dendrite extension in α-MSH-induced melanogenesis of SK-MEL-2 human melanoma cells. CTM also suppressed α-MSH-induced chemotactic migration as well as the expressions of melanogenesis factors TRP-1, TRP-2 and MITF in α-MSH-treated SK-MEL-2 cells. Meanwhile, gene silencing of Tgase-2 suppressed dendrite extension and the expressions of TRP-1 and TRP-2 in α-MSH-treated SK-MEL-2 cells. Overall, these findings suggested that CTM suppresses α-MSH-induced melanogenesis via Tgase-2 inhibition and that therefore, Tgase-2 might be a new target in hyperpigmentation disorder therapy.

Screen-Printed Electrodes: New Tools for Developing Microbial Electrochemistry at Microscale Level

Directory of Open Access Journals (Sweden)

Marta Estevez-Canales

2015-11-01

Full Text Available Microbial electrochemical technologies (METs have a number of potential technological applications. In this work, we report the use of screen-printed electrodes (SPEs as a tool to analyze the microbial electroactivity by using Geobacter sulfurreducens as a model microorganism. We took advantage of the small volume required for the assays (75 μL and the disposable nature of the manufactured strips to explore short-term responses of microbial extracellular electron transfer to conductive materials under different scenarios. The system proved to be robust for identifying the bioelectrochemical response, while avoiding complex electrochemical setups, not available in standard biotechnology laboratories. We successfully validated the system for characterizing the response of Geobacter sulfurreducens in different physiological states (exponential phase, stationary phase, and steady state under continuous culture conditions revealing different electron transfer responses. Moreover, a combination of SPE and G. sulfurreducens resulted to be a promising biosensor for quantifying the levels of acetate, as well as for performing studies in real wastewater. In addition, the potential of the technology for identifying electroactive consortia was tested, as an example, with a mixed population with nitrate-reducing capacity. We therefore present SPEs as a novel low-cost platform for assessing microbial electrochemical activity at the microscale level.

Sustainable remediation: electrochemically assisted microbial dechlorination of tetrachloroethene-contaminated groundwater.

Science.gov (United States)

Patil, Sayali S; Adetutu, Eric M; Rochow, Jacqueline; Mitchell, James G; Ball, Andrew S

2014-01-01

Microbial electric systems (MESs) hold significant promise for the sustainable remediation of chlorinated solvents such as tetrachlorethene (perchloroethylene, PCE). Although the bio-electrochemical potential of some specific bacterial species such as Dehalcoccoides and Geobacteraceae have been exploited, this ability in other undefined microorganisms has not been extensively assessed. Hence, the focus of this study was to investigate indigenous and potentially bio-electrochemically active microorganisms in PCE-contaminated groundwater. Lab-scale MESs were fed with acetate and carbon electrode/PCE as electron donors and acceptors, respectively, under biostimulation (BS) and BS-bioaugmentation (BS-BA) regimes. Molecular analysis of the indigenous groundwater community identified mainly Spirochaetes, Firmicutes, Bacteroidetes, and γ and δ-Proteobacteria. Environmental scanning electron photomicrographs of the anode surfaces showed extensive indigenous microbial colonization under both regimes. This colonization and BS resulted in 100% dechlorination in both treatments with complete dechlorination occurring 4 weeks earlier in BS-BA samples and up to 11.5 μA of current being generated. The indigenous non-Dehalococcoides community was found to contribute significantly to electron transfer with ∼61% of the current generated due to their activities. This study therefore shows the potential of the indigenous non-Dehalococcoides bacterial community in bio-electrochemically reducing PCE that could prove to be a cost-effective and sustainable bioremediation practice. © 2013 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

The benzoquinone-mediated electrochemical microbial biosensor for water biotoxicity assay

International Nuclear Information System (INIS)

Li, Jiuming; Yu, Yuan; Wang, Yuning; Qian, Jun; Zhi, Jinfang

2013-01-01

Graphical abstract: The mediator can participate in microorganism respiration, accept the electrons from respiratory chains, and therefore be reduced by microorganism. The re-oxidization currents of mediators on electrode can reflect the microbial activity, and when respiration is suppressed by toxicants, it can be detected by the resulting change of currents. Unlike other biotoxicity tests, which record the toxic effect after a fixed time for incubation of biocomponents and toxicants, this mediated whole cell biosensor can provide a real-time monitor of the microbial activity during the measurement. -- Abstract: A simple mediated microbial biosensor providing real-time monitoring of water quality and evaluation of biotoxicity was fabricated by entrapping Escherichia coli (E. coli) cells in gelatin on glassy carbon electrode with benzoquinone as the redox mediator. The biotoxicity assay was based on the respiratory activity of E. coli cells estimated by the oxidation current of microbially reduced benzoquinone. The neutrality and lipophilicity rendered benzoquinone better efficiency than ferricyanide in mediated microbial reactions. After the optimization of preparation conditions, the prepared microbial biosensors have measured several common toxicants with different concentrations. In addition, the biotoxicity of binary mixtures of heavy metals and wastewater were investigated. The fabricated biosensor exhibited good repeatability and stability in the biotoxicity measurements

Karakterisasi dan Aplikasi Enzim Transglutaminase dari Streptoverticillium ladakanum pada Daging Lumat IKan Mata Goyang

Directory of Open Access Journals (Sweden)

Yusro Nuri Fawzya

2011-12-01

Full Text Available Telah dilakukan karakterisasi enzim transglutaminase mikroba (MTGase yang diproduksi dari Streptoverticillium ladakanumdengan menggunakan media yang mengandung limbah cair tahu dan hidrolisat tepung tapioka. Enzim MTGase yang dikarakteris as i merupakan enzim kasar yang telah dipekatkan menggunakan ultrafiltrasi dan dikeringbekukan. Enzim ini kemudian diaplikasikan pada daging lumat ikan mata goyang (Priacanthus macracanthus lalu diamati sifat fisik (tekstur produk restrukturisasi yang dihasilkan. Sebagai pembanding,  dilakukan aplikasi TGase komersial (KTGase pada daging lumat yang sama. Penambahan TGase dilakukan dengan 2 cara, yaitu:  (1 bersama-sama dengan garam NaCl 1%, (2 bersama-sama dengan garam NaCl 1% dan sodium kaseinat 1%. Sebagai control adalah daging lumat ditambah garam N aCl 1% (tanpa penambahan enzim TGase. Hasil penelitian menunjukkan bahwa MTGase dari S. ladakanumbekerja optimum pada pH 8 dan suhu 55°C. Aktivitas enzim ini relatif tidak terpengaruh oleh adanya ion logam Ca2+,Mg2+, Na+, dan K+maupun inhibitor seperti ethylenediaminetetraacetic acid(EDTA, dan phenylmethyl-sulfonylfluoride(PMSF. Enzim MTGase tanpa penambahan sodium kaseinat menunjukkan kemampuan membentuk gel yang tidak berbeda dengan TGase komersial, menghasilkan kekuatan gel 16848 g mm dan nilai kekenyalan 0,97. Enzim ini juga terbukti dapat meningkatkan kekuatan gel, kekenyalan, dan kepadatan produk restrukturisasi daging lumat ikan yang hanya ditambah garam NaCl saja atau yang ditambah garam NaCl dan sodium kaseinat.

Hydrogen production profiles using furans in microbial electrolysis cells.

Science.gov (United States)

Catal, Tunc; Gover, Tansu; Yaman, Bugra; Droguetti, Jessica; Yilancioglu, Kaan

2017-06-01

Microbial electrochemical cells including microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are novel biotechnological tools that can convert organic substances in wastewater or biomass into electricity or hydrogen. Electroactive microbial biofilms used in this technology have ability to transfer electrons from organic compounds to anodes. Evaluation of biofilm formation on anode is crucial for enhancing our understanding of hydrogen generation in terms of substrate utilization by microorganisms. In this study, furfural and hydroxymethylfurfural (HMF) were analyzed for hydrogen generation using single chamber membrane-free MECs (17 mL), and anode biofilms were also examined. MECs were inoculated with mixed bacterial culture enriched using chloroethane sulphonate. Hydrogen was succesfully produced in the presence of HMF, but not furfural. MECs generated similar current densities (5.9 and 6 mA/cm 2 furfural and HMF, respectively). Biofilm samples obtained on the 24th and 40th day of cultivation using aromatic compounds were evaluated by using epi-fluorescent microscope. Our results show a correlation between biofilm density and hydrogen generation in single chamber MECs.

Powering microbes with electricity: direct electron transfer from electrodes to microbes.

Science.gov (United States)

Lovley, Derek R

2011-02-01

The discovery of electrotrophs, microorganisms that can directly accept electrons from electrodes for the reduction of terminal electron acceptors, has spurred the investigation of a wide range of potential applications. To date, only a handful of pure cultures have been shown to be capable of electrotrophy, but this process has also been inferred in many studies with undefined consortia. Potential electron acceptors include: carbon dioxide, nitrate, metals, chlorinated compounds, organic acids, protons and oxygen. Direct electron transfer from electrodes to cells has many advantages over indirect electrical stimulation of microbial metabolism via electron shuttles or hydrogen production. Supplying electrons with electrodes for the bioremediation of chlorinated compounds, nitrate or toxic metals may be preferable to adding organic electron donors or hydrogen to the subsurface or bioreactors. The most transformative application of electrotrophy may be microbial electrosynthesis in which carbon dioxide and water are converted to multi-carbon organic compounds that are released extracellularly. Coupling photovoltaic technology with microbial electrosynthesis represents a novel photosynthesis strategy that avoids many of the drawbacks of biomass-based strategies for the production of transportation fuels and other organic chemicals. The mechanisms for direct electron transfer from electrodes to microorganisms warrant further investigation in order to optimize envisioned applications. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Regulation of electron transfer processes affects phototrophic mat structure and activity

OpenAIRE

Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; Reardon, Patrick N.; Lindemann, Stephen R.; Fredrickson, James K.; Call, Douglas R.; Beyenal, Haluk

2015-01-01

Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located ne...

Microbial electrocatalysis with Geobacter sulfurreducens biofilm on stainless steel cathodes

OpenAIRE

Dumas, Claire; Basséguy, Régine; Bergel, Alain

2008-01-01

Stainless steel and graphite electrodes were individually addressed and polarized at−0.60V vs. Ag/AgCl in reactors filled with a growth medium that contained 25mM fumarate as the electron acceptor and no electron donor, in order to force the microbial cells to use the electrode as electron source. When the reactor was inoculated with Geobacter sulfurreducens, the current increased and stabilized at average values around 0.75Am−2 for graphite and 20.5Am−2 for stainless steel. Cyclic voltamm...

Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

International Nuclear Information System (INIS)

Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E.; Jaczynski, Jacek

2011-01-01

Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D 10 -value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D 10 -values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D 10 -values for the ATCC strain were 0.59±0.031 and 0.46±0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D 10 -values increased (P 0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P 10 -values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

Synthetic microbial ecology and the dynamic interplay between microbial genotypes.

Science.gov (United States)

Dolinšek, Jan; Goldschmidt, Felix; Johnson, David R

2016-11-01

Assemblages of microbial genotypes growing together can display surprisingly complex and unexpected dynamics and result in community-level functions and behaviors that are not readily expected from analyzing each genotype in isolation. This complexity has, at least in part, inspired a discipline of synthetic microbial ecology. Synthetic microbial ecology focuses on designing, building and analyzing the dynamic behavior of ‘ecological circuits’ (i.e. a set of interacting microbial genotypes) and understanding how community-level properties emerge as a consequence of those interactions. In this review, we discuss typical objectives of synthetic microbial ecology and the main advantages and rationales of using synthetic microbial assemblages. We then summarize recent findings of current synthetic microbial ecology investigations. In particular, we focus on the causes and consequences of the interplay between different microbial genotypes and illustrate how simple interactions can create complex dynamics and promote unexpected community-level properties. We finally propose that distinguishing between active and passive interactions and accounting for the pervasiveness of competition can improve existing frameworks for designing and predicting the dynamics of microbial assemblages.

Evolving Microbial Communities in Cellulose-Fed Microbial Fuel Cell

Directory of Open Access Journals (Sweden)

Renata Toczyłowska-Mamińska

2018-01-01

Full Text Available The abundance of cellulosic wastes make them attractive source of energy for producing electricity in microbial fuel cells (MFCs. However, electricity production from cellulose requires obligate anaerobes that can degrade cellulose and transfer electrons to the electrode (exoelectrogens, and thus most previous MFC studies have been conducted using two-chamber systems to avoid oxygen contamination of the anode. Single-chamber, air-cathode MFCs typically produce higher power densities than aqueous catholyte MFCs and avoid energy input for the cathodic reaction. To better understand the bacterial communities that evolve in single-chamber air-cathode MFCs fed cellulose, we examined the changes in the bacterial consortium in an MFC fed cellulose over time. The most predominant bacteria shown to be capable electron generation was Firmicutes, with the fermenters decomposing cellulose Bacteroidetes. The main genera developed after extended operation of the cellulose-fed MFC were cellulolytic strains, fermenters and electrogens that included: Parabacteroides, Proteiniphilum, Catonella and Clostridium. These results demonstrate that different communities evolve in air-cathode MFCs fed cellulose than the previous two-chamber reactors.

Relating Anaerobic Digestion Microbial Community and Process Function.

Science.gov (United States)

Venkiteshwaran, Kaushik; Bocher, Benjamin; Maki, James; Zitomer, Daniel

2015-01-01

Anaerobic digestion (AD) involves a consortium of microorganisms that convert substrates into biogas containing methane for renewable energy. The technology has suffered from the perception of being periodically unstable due to limited understanding of the relationship between microbial community structure and function. The emphasis of this review is to describe microbial communities in digesters and quantitative and qualitative relationships between community structure and digester function. Progress has been made in the past few decades to identify key microorganisms influencing AD. Yet, more work is required to realize robust, quantitative relationships between microbial community structure and functions such as methane production rate and resilience after perturbations. Other promising areas of research for improved AD may include methods to increase/control (1) hydrolysis rate, (2) direct interspecies electron transfer to methanogens, (3) community structure-function relationships of methanogens, (4) methanogenesis via acetate oxidation, and (5) bioaugmentation to study community-activity relationships or improve engineered bioprocesses.

Production and Consumption of Hydrogen in Hot Spring Microbial Mats Dominated by a Filamentous Anoxygenic Photosynthetic Bacterium

Science.gov (United States)

Otaki, Hiroyo; Everroad, R. Craig; Matsuura, Katsumi; Haruta, Shin

2012-01-01

Microbial mats containing the filamentous anoxygenic photosynthetic bacterium Chloroflexus aggregans develop at Nakabusa hot spring in Japan. Under anaerobic conditions in these mats, interspecies interaction between sulfate-reducing bacteria as sulfide producers and C. aggregans as a sulfide consumer has been proposed to constitute a sulfur cycle; however, the electron donor utilized for microbial sulfide production at Nakabusa remains to be identified. In order to determine this electron donor and its source, ex situ experimental incubation of mats was explored. In the presence of molybdate, which inhibits biological sulfate reduction, hydrogen gas was released from mat samples, indicating that this hydrogen is normally consumed as an electron donor by sulfate-reducing bacteria. Hydrogen production decreased under illumination, indicating that C. aggregans also functions as a hydrogen consumer. Small amounts of hydrogen may have also been consumed for sulfur reduction. Clone library analysis of 16S rRNA genes amplified from the mats indicated the existence of several species of hydrogen-producing fermentative bacteria. Among them, the most dominant fermenter, Fervidobacterium sp., was successfully isolated. This isolate produced hydrogen through the fermentation of organic carbon. Dispersion of microbial cells in the mats resulted in hydrogen production without the addition of molybdate, suggesting that simultaneous production and consumption of hydrogen in the mats requires dense packing of cells. We propose a cyclic electron flow within the microbial mats, i.e., electron flow occurs through three elements: S (elemental sulfur, sulfide, sulfate), C (carbon dioxide, organic carbon) and H (di-hydrogen, protons). PMID:22446313

Microbial processes relevant for the long-term performance of radioactive waste repositories in clays

International Nuclear Information System (INIS)

Meleshyn, Artur

2012-01-01

Document available in extended abstract form only. A number of investigations on occurrence and viability of microbes in compacted clays have been aimed at studying possible microbial effects on long-term performance of a deep geological repository (DGR) for high-level radioactive waste (HLW) and spent nuclear fuel (SF). Compacted clays are considered in current DGR designs either as a buffer material or as a host rock. The primary purpose of the present work was to qualitatively evaluate the relevance of microbial activity for the long-term performance of a DGR and to identify which safety-relevant processes and properties can be potentially influenced by this activity. The present analysis identified eight clay properties essential for maintaining safety functions of containment and retardation of the disposal system - swelling pressure, specific surface area, cation exchange capacity, anion sorption capacity, porosity, permeability, fluid pressure, plasticity - which can potentially be influenced by microbial processes in clay buffer and Clay-stone within a DGR for HLW/SF. Iron(III)- and sulphate-reducing, fermentative, methane-producing and oxidizing microbes can be considered to be present in any clay formation. Each habitat includes a massive number of microbial niches with perhaps only a small proportion of the species being metabolically active at the habitat's conditions, the remainder becoming not extinct. Moreover, clays contain electron donors and electron acceptors in amounts sufficient for these microbes to remain active during very long periods of time. Additional sources of electron donors or electron acceptors will inevitably be added to the repository system as a result of DGR excavation, placement of radioactive waste as well as backfilling and sealing of the DGR. In no case should the potential impact of microbes be underestimated based on a possible argument of comparably low biomass of the microbes in contact with metal surfaces or dissolved

Microbial fuel cells for clogging assessment in constructed wetlands

International Nuclear Information System (INIS)

Corbella, Clara; García, Joan; Puigagut, Jaume

2016-01-01

Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20 kg TS·m"− "3 CW·year"− "1 at the beginning of the study period up to ca. 250 kg TS·m"− "3 CW·year"− "1 at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2 years (ca. 0.5 kg TS·m"–"3CW) to ca. 5 years (ca. 10 kg TS·m"–"3CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5 years of clogging (ca. 10 kg TS·m"–"3CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. - Highlights: • Microbial fuel cells are used as tool for clogging assessment in constructed wetlands. • Microbial fuel cells were loaded with sludge from constructed wetlands. • Sludge retained within the systems simulated a clogging time ranging from 0.2 to ca. 5 years. • Electrons transferred decreased potentially as function of sludge loading. • Microbial fuel cells have potential for clogging assessment

Regulation of electron transfer processes affects phototrophic mat structure and activity

Science.gov (United States)

Ha, Phuc T.; Renslow, Ryan S.; Atci, Erhan; Reardon, Patrick N.; Lindemann, Stephen R.; Fredrickson, James K.; Call, Douglas R.; Beyenal, Haluk

2015-01-01

Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that variation in the

Regulation of electron transfer processes affects phototrophic mat structure and activity

Directory of Open Access Journals (Sweden)

Haluk eBeyenal

2015-09-01

Full Text Available Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA. We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl (cathodic mat system and +300 mVAg/AgCl (anodic mat system and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both anodic and cathodic mat systems. Interestingly, the cathodic mats generated the highest reducing current at the same time points that the anodic mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the cathodic mats than in the anodic mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the cathodic mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that

Regulation of electron transfer processes affects phototrophic mat structure and activity.

Science.gov (United States)

Ha, Phuc T; Renslow, Ryan S; Atci, Erhan; Reardon, Patrick N; Lindemann, Stephen R; Fredrickson, James K; Call, Douglas R; Beyenal, Haluk

2015-01-01

Phototrophic microbial mats are among the most diverse ecosystems in nature. These systems undergo daily cycles in redox potential caused by variations in light energy input and metabolic interactions among the microbial species. In this work, solid electrodes with controlled potentials were placed under mats to study the electron transfer processes between the electrode and the microbial mat. The phototrophic microbial mat was harvested from Hot Lake, a hypersaline, epsomitic lake located near Oroville (Washington, USA). We operated two reactors: graphite electrodes were polarized at potentials of -700 mVAg/AgCl [cathodic (CAT) mat system] and +300 mVAg/AgCl [anodic (AN) mat system] and the electron transfer rates between the electrode and mat were monitored. We observed a diel cycle of electron transfer rates for both AN and CAT mat systems. Interestingly, the CAT mats generated the highest reducing current at the same time points that the AN mats showed the highest oxidizing current. To characterize the physicochemical factors influencing electron transfer processes, we measured depth profiles of dissolved oxygen (DO) and sulfide in the mats using microelectrodes. We further demonstrated that the mat-to-electrode and electrode-to-mat electron transfer rates were light- and temperature-dependent. Using nuclear magnetic resonance (NMR) imaging, we determined that the electrode potential regulated the diffusivity and porosity of the microbial mats. Both porosity and diffusivity were higher in the CAT mats than in the AN mats. We also used NMR spectroscopy for high-resolution quantitative metabolite analysis and found that the CAT mats had significantly higher concentrations of osmoprotectants such as betaine and trehalose. Subsequently, we performed amplicon sequencing across the V4 region of the 16S rRNA gene of incubated mats to understand the impact of electrode potential on microbial community structure. These data suggested that variation in the

Application of electron irradiation to food containers and packaging materials

International Nuclear Information System (INIS)

Ueno, Koji

2010-01-01

Problems caused by microbial contamination and hazardous chemicals have attracted much attention in the food industry. The number of systems such as hygienic management systems and Hazard Analysis Critical Control Point (HACCP) systems adopted in the manufacturing process is increasing. As manufacturing process control has become stricter, stricter control is also required for microbial control for containers and packaging materials (from disinfection to sterilization). Since safe and reliable methods for sterilizing food containers and packaging materials that leave no residue are required, electron beam sterilization used for medical equipment has attracted attention from the food industry. This paper describes an electron irradiation facility, methods for applying electron beams to food containers and packaging materials, and products irradiated with electron beams. (author)

Microbial ecology-based engineering of Microbial Electrochemical Technologies.

Science.gov (United States)

Koch, Christin; Korth, Benjamin; Harnisch, Falk

2018-01-01

Microbial ecology is devoted to the understanding of dynamics, activity and interaction of microorganisms in natural and technical ecosystems. Bioelectrochemical systems represent important technical ecosystems, where microbial ecology is of highest importance for their function. However, whereas aspects of, for example, materials and reactor engineering are commonly perceived as highly relevant, the study and engineering of microbial ecology are significantly underrepresented in bioelectrochemical systems. This shortfall may be assigned to a deficit on knowledge and power of these methods as well as the prerequisites for their thorough application. This article discusses not only the importance of microbial ecology for microbial electrochemical technologies but also shows which information can be derived for a knowledge-driven engineering. Instead of providing a comprehensive list of techniques from which it is hard to judge the applicability and value of information for a respective one, this review illustrates the suitability of selected techniques on a case study. Thereby, best practice for different research questions is provided and a set of key questions for experimental design, data acquisition and analysis is suggested. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Microbial Transformations of Actinides and Fission Products in Radioactive Waste

Energy Technology Data Exchange (ETDEWEB)

Francis, A. J. [Pohang Univ. Science and Technology, Pohang (Korea, Republic of)

2011-07-01

The environmental factors that can affect microbial growth and activity include moisture, temperature, ph, Eh, availability of organic and inorganic nutrients, and radiation. The microbial activity in a specific repository is influenced by the ambient environment of the repository, and the materials to be emplaced. For example, a repository in unsaturated igneous rock formations such as volcanic tuff rocks at Yucca Mountain is generally expected to be oxidizing; a repository in a hydrologically expected to be oxidizing; a repository in a hydrologically saturated zone, especially in sedimentary rocks, could be reducing. Sedimentary rocks contain a certain amount of organic matter, which may stimulate microbial activities and, thus maintain the repository and its surrounding areas at reducing conditions. Although the impacts of microbial activity on high-level nuclear waste and the long-term performance of the repository have not fully investigated, little microbial activity is expected in the near-field because of the radiation, lack of nutrients and the harsh conditions. However in the far-field microbial effects could be significant. Much of our understanding of the microbial effects on radionuclides stems from studies conducted with selected transuranic elements and fission products and limited studies with low-level radioactive wastes. Significant aerobic- and anaerobic-microbial activity is expected to occur in the waste because of the presence of electron donors and acceptors. The actinides initially may be present as soluble- or insoluble-forms but, after disposal, may be converted from one to the other by microorganisms. The direct enzymatic or indirect non-enzymatic actions of microbes could alter the speciation, solubility, and sorption properties of the actinides, thereby increasing or decreasing their concentrations in solution.

Microbial bebop: creating music from complex dynamics in microbial ecology.

Science.gov (United States)

Larsen, Peter; Gilbert, Jack

2013-01-01

In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm.) from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

Science.gov (United States)

Yuen, Jonathan D.; Walper, Scott A.; Melde, Brian J.; Daniele, Michael A.; Stenger, David A.

2017-01-01

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L-1.

Engineering microbial electrocatalysis for chemical and fuel production.

Science.gov (United States)

Rosenbaum, Miriam A; Henrich, Alexander W

2014-10-01

In many biotechnological areas, metabolic engineering and synthetic biology have become core technologies for biocatalyst development. Microbial electrocatalysis for biochemical and fuel production is still in its infancy and reactions rates and the product spectrum are currently very low. Therefore, molecular engineering strategies will be crucial for the advancement and realization of many new bioproduction routes using electroactive microorganisms. The complex and unresolved biochemistry and physiology of extracellular electron transfer and the lack of molecular tools for these new non-model hosts for genetic engineering constitute the major challenges for this effort. This review is providing an insight into the current status, challenges and promising approaches of pathway engineering for microbial electrocatalysis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microbial diversity of a high salinity oil field

International Nuclear Information System (INIS)

Neria, I.; Gales, G.; Alazard, D.; Ollivier, B.; Borgomano, J.; Joulian, C.

2009-01-01

This work is a preliminary study to investigate the microbial diversity of an onshore oil field. It aim to compare results obtained from molecular methods, physicochemical analyses and cultivation. A core of 1150 m depth sediments ( in situ T=45 degree centigrade) was collected and immediately frozen with liquid nitrogen prior to further investigation. Macroscopic and Scanning Electron Microscopy analyses were performed. (Author)

Phylogenetic analysis of TCE-dechlorinating consortia enriched on a variety of electron donors.

Science.gov (United States)

Freeborn, Ryan A; West, Kimberlee A; Bhupathiraju, Vishvesh K; Chauhan, Sadhana; Rahm, Brian G; Richardson, Ruth E; Alvarez-Cohen, Lisa

2005-11-01

Two rapidly fermented electron donors, lactate and methanol, and two slowly fermented electron donors, propionate and butyrate, were selected for enrichment studies to evaluate the characteristics of anaerobic microbial consortia that reductively dechlorinate TCE to ethene. Each electron donor enrichment subculture demonstrated the ability to dechlorinate TCE to ethene through several serial transfers. Microbial community analyses based upon 16S rDNA, including terminal restriction fragment length polymorphism (T-RFLP) and clone library/sequencing, were performed to assess major changes in microbial community structure associated with electron donors capable of stimulating reductive dechlorination. Results demonstrated that five phylogenic subgroups or genera of bacteria were present in all consortia, including Dehalococcoides sp., low G+C Gram-positives (mostly Clostridium and Eubacterium sp.), Bacteroides sp., Citrobacter sp., and delta Proteobacteria (mostly Desulfovibrio sp.). Phylogenetic association indicates that only minor shifts in the microbial community structure occurred between the four alternate electron donor enrichments and the parent consortium. Inconsistent detection of Dehalococcoides spp. in clone libraries and T-RFLP of enrichment subcultures was resolved using quantitative polymerase chain reaction (Q-PCR). Q-PCR with primers specific to Dehalococcoides 16S rDNA resulted in positive detection of this species in all enrichments. Our results suggest that TCE-dechlorinating consortia can be stably maintained on a variety of electron donors and that quantities of Dehalococcoides cells detected with Dehalococcoides specific 16S rDNA primer/probe sets do not necessarily correlate well with solvent degradation rates.

Biofilm and dental implant: The microbial link

Directory of Open Access Journals (Sweden)

Sangeeta Dhir

2013-01-01

Full Text Available Mouth provides a congenial environment for the growth of the microorganisms as compared to any other part of the human body by exhibiting an ideal nonshedding surface. Dental plaque happens to be a diverse community of the microorganisms found on the tooth surface. Periodontal disease and the peri-implant disease are specific infections that are originating from these resident microbial species when the balance between the host and the microbial pathogenicity gets disrupted. This review discusses the biofilms in relation to the peri-implant region, factors affecting its presence, and the associated treatment to manage this complex microbial colony. Search Methodology: Electronic search of the medline was done with the search words: Implants and biofilms/dental biofilm formation/microbiology at implant abutment interface/surface free energy/roughness and implant, periimplantitis/local drug delivery and dental implant. Hand search across the journals - clinical oral implant research, implant dentistry, journal of dental research, international journal of oral implantology, journal of prosthetic dentistry, perioodntology 2000, journal of periodontology were performed. The articles included in the review comprised of in vivo studies, in vivo (animal and human studies, abstracts, review articles.

Strategies for microbial synthesis of high-value phytochemicals

Science.gov (United States)

Li, Sijin; Li, Yanran; Smolke, Christina D.

2018-03-01

Phytochemicals are of great pharmaceutical and agricultural importance, but often exhibit low abundance in nature. Recent demonstrations of industrial-scale production of phytochemicals in yeast have shown that microbial production of these high-value chemicals is a promising alternative to sourcing these molecules from native plant hosts. However, a number of challenges remain in the broader application of this approach, including the limited knowledge of plant secondary metabolism and the inefficient reconstitution of plant metabolic pathways in microbial hosts. In this Review, we discuss recent strategies to achieve microbial biosynthesis of complex phytochemicals, including strategies to: (1) reconstruct plant biosynthetic pathways that have not been fully elucidated by mining enzymes from native and non-native hosts or by enzyme engineering; (2) enhance plant enzyme activity, specifically cytochrome P450 activity, by improving efficiency, selectivity, expression or electron transfer; and (3) enhance overall reaction efficiency of multi-enzyme pathways by dynamic control, compartmentalization or optimization with the host's metabolism. We also highlight remaining challenges to — and future opportunities of — this approach.

Microbial bebop: creating music from complex dynamics in microbial ecology.

Directory of Open Access Journals (Sweden)

Peter Larsen

Full Text Available In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm. from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

Assembly and Function of a Spore Coat-Associated Transglutaminase of Bacillus subtilis

Science.gov (United States)

Zilhão, Rita; Isticato, Rachele; Martins, Lígia O.; Steil, Leif; Völker, Uwe; Ricca, Ezio; Moran, Charles P.; Henriques, Adriano O.

2005-01-01

The assembly of a multiprotein coat around the Bacillus subtilis spore confers resistance to lytic enzymes and noxious chemicals and ensures normal germination. Part of the coat is cross-linked and resistant to solubilization. The coat contains ɛ-(γ-glutamyl)lysyl cross-links, and the expression of the gene (tgl) for a spore-associated transglutaminase was shown before to be required for the cross-linking of coat protein GerQ. Here, we have investigated the assembly and function of Tgl. We found that Tgl associates, albeit at somewhat reduced levels, with the coats of mutants that are unable to assemble the outer coat (cotE), that are missing the inner coat and with a greatly altered outer coat (gerE), or that are lacking discernible inner and outer coat structures (cotE gerE double mutant). This suggests that Tgl is present at various levels within the coat lattice. The assembly of Tgl occurs independently of its own activity, as a single amino acid substitution of a cysteine to an alanine (C116A) at the active site of Tgl does not affect its accumulation or assembly. However, like a tgl insertional mutation, the tglC116A allele causes increased extractability of polypeptides of about 40, 28, and 16 kDa in addition to GerQ (20 kDa) and affects the structural integrity of the coat. We show that most Tgl is assembled onto the spore surface soon after its synthesis in the mother cell under σK control but that the complete insolubilization of at least two of the Tgl-controlled polypeptides occurs several hours later. We also show that a multicopy allele of tgl causes increased assembly of Tgl and affects the assembly, structure, and functional properties of the coat. PMID:16267299

Microbial transformations of nitrogen, sulfur and iron dictate vegetation composition in wetlands: a review

Directory of Open Access Journals (Sweden)

Leon P.M. Lamers

2012-04-01

Full Text Available The majority of studies on rhizospheric interactions between microbial communities and vegetation focus on pathogens, mycorrhizal symbiosis, and/or carbon transformations. Although the biogeochemical transformations of nitrogen (N, sulfur (S and iron (Fe have profound effects on plants, these effects have received far less attention. Firstly, all three elements are plant nutrients, and microbial activity significantly changes their mobility and availability. Secondly, microbial oxidation with oxygen supplied by radial oxygen loss (ROL from roots in wetlands causes acidification, while reduction using alternative electron acceptors leads to generation of alkalinity, affecting pH in the rhizosphere and hence plant composition. Thirdly, reduced species of all three elements may become phytotoxic. In addition, Fe cycling is tightly linked to that of S and phosphorus (P. As water level fluctuations are very common in wetlands, rapid changes in the availability of oxygen and alternative terminal electron acceptors will result in strong changes in the prevalent microbial redox reactions, with significant effects on plant growth. Depending on geological and hydrological settings, these interacting microbial transformations change the conditions and resource availability for plants, which are strong drivers of vegetation development and composition by changing relative competitive strengths. Conversely, microbial composition is strongly driven by vegetation composition. Therefore, the combination of micro- and macroecological knowledge is essential to understand the biogeochemical and biological key factors driving heterogeneity and total (i.e., micro-macro community composition at different spatial and temporal scales. As N and S inputs have drastically increased due to anthropogenic forcing and Fe inputs have decreased at a global scale, this combined approach has become even more urgent.

Improvement of physicochemical and rheological properties of kombucha fermented milk products by addition of transglutaminase and whey protein concentrate

Directory of Open Access Journals (Sweden)

Iličić Mirela D.

2016-01-01

Full Text Available The objective of this work was to investigate the effect of addition of transglutaminase (TG-0.02%, w/w and whey protein concentrate (WPC-0.03%, w/w, on quality of kombucha fermented milk product. Samples were prepared from pasteurized semi-skim milk (0.9%, w/w fat and kombucha inoculum (10%, v/v. The pH values were measured during the fermentation of milk (lasted until reached 4.5. Syneresis, water holding capacity and the product texture (firmness and consistency, were assessed after production. Rheological properties of kombucha fermented milk samples were measured during ten days of storage. The sample containing TG had the lowest syneresis (21 ml, the highest water holding capacity (62% and the highest textural characteristics (firmness - 23.99g, consistency - 626.54gs after production. The addition of WPC to milk improved the rheological properties, while the addition of TG improved it even to a significantly greater extent after the production and during 10 days of the storage. [Projekat Ministarstva nauke Republike Srbije, br. 46009

Extracellular polymeric substances are transient media for microbial extracellular electron transfer

DEFF Research Database (Denmark)

Xiao, Yong; Zhang, Enhua; Zhang, Jingdong

2017-01-01

in microbiology and microbial exploitation for mineral bio-respiration, pollutant conversion, and bioenergy production. We have addressed these challenges by comparing pure and EPS-depleted samples of three representative electrochemically active strains viz Gram-negative Shewanella oneidensis MR-1, Gram......-positive Bacillus sp. WS-XY1, and yeast Pichia stipites using technology from electrochemistry, spectroscopy, atomic force microscopy, and microbiology. Voltammetry discloses redox signals from cytochromes and flavins in intact MR-1 cells, whereas stronger signals from cytochromes and additional signals from both...

Nanoporous Mo2C functionalized 3D carbon architecture anode for boosting flavins mediated interfacial bioelectrocatalysis in microbial fuel cells

Science.gov (United States)

Zou, Long; Lu, Zhisong; Huang, Yunhong; Long, Zhong-er; Qiao, Yan

2017-08-01

An efficient microbial electrocatalysis in microbial fuel cells (MFCs) needs both high loading of microbes (biocatalysts) and robust interfacial electron transfer from microbes to electrode. Herein a nanoporous molybdenum carbide (Mo2C) functionalized carbon felt electrode with rich 3D hierarchical porous architecture is applied as MFC anode to achieve superior electrocatalytic performance. The nanoporous Mo2C functionalized anode exhibits strikingly improved microbial electrocatalysis in MFCs with 5-fold higher power density and long-term stability of electricity production. The great enhancement is attributed to the introduction of rough Mo2C nanostructural interface into macroporous carbon architecture for promoting microbial growth with great excretion of endogenous electron shuttles (flavins) and rich available nanopores for enlarging electrochemically active surface area. Importantly, the nanoporous Mo2C functionalized anode is revealed for the first time to have unique electrocatalytic activity towards redox reaction of flavins with more negative redox potential, indicating a more favourable thermodynamic driving force for anodic electron transfer. This work not only provides a promising electrode for high performance MFCs but also brings up a new insight into the effect of nanostructured materials on interfacial bioelectrocatalysis.

Microbial radio-resistance of Salmonella Typhimurium in egg increases due to repetitive irradiation with electron beam

Energy Technology Data Exchange (ETDEWEB)

Tesfai, Adiam T.; Beamer, Sarah K.; Matak, Kristen E. [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States); Jaczynski, Jacek, E-mail: Jacek.Jaczynski@mail.wvu.ed [West Virginia University, Division of Animal and Nutritional Sciences, PO Box 6108, Morgantown, WV 26508 (United States)

2011-04-15

Ionizing radiation improves food safety. However, foodborne pathogens develop increased resistance in response to sub-lethal stresses such as heat, pH, antibiotics, etc. Therefore, it is hypothesized that foodborne pathogens may develop increased radio-resistance to electron beam (e-beam) radiation. The objective was to determine if D{sub 10}-value for Salmonella Typhimurium in de-shelled raw egg (egg white and yolk mixed together) increases due to repetitive processing with e-beam at sub-lethal doses. Survivors were enumerated on non-selective (TSA) and selective (XLD) media. Survivors from the highest dose were isolated and used in subsequent e-beam cycle. This process was repeated four times for a total of five e-beam cycles. D{sub 10}-values for S. Typhimurium enumerated on TSA and XLD following each e-beam cycle were calculated as inverse reciprocal of the slope of survivor curves. D{sub 10}-values for the ATCC strain were 0.59{+-}0.031 and 0.46{+-}0.022 kGy on TSA and XLD, respectively. However, following the fifth e-beam cycle, the respective D{sub 10}-values increased (P<0.05) to 0.69{+-}0.026 and 0.61{+-}0.029 kGy, respectively. S. Typhimurium showed a trend (P>0.05) to develop radio-resistance faster on selective media, likely due to facilitated selection of radio-resistant cells within microbial population following each e-beam cycle. For all five e-beam cycles, S. Typhimurium had higher (P<0.05) D{sub 10}-values on non-selective media, indicating that sub-lethal injury followed by cellular repair and recovery are important for radio-resistance and inactivation of this microorganism. This study demonstrated that e-beam efficiently inactivates S. Typhimurium in raw egg; however, similar to other inactivation techniques and factors affecting microbial growth, S. Typhimurium develops increased radio-resistance if repetitively processed with e-beam at sub-lethal doses.

Biodistribution and catabolism of 18F-labelled isopeptide N(epsilon)-(gamma-glutamyl)-L-lysine.

Science.gov (United States)

Hultsch, C; Bergmann, R; Pawelke, B; Pietzsch, J; Wuest, F; Johannsen, B; Henle, T

2005-12-01

Isopeptide bonds between the epsilon-amino group of lysine and the gamma-carboxamide group of glutamine are formed during strong heating of pure proteins or, more important, by enzymatic reaction mediated by transglutaminases. Despite the wide use of a microbial transglutaminase in food biotechnology, up to now little is known about the metabolic fate of the isopeptide N(epsilon)-(gamma-glutamyl)-L-lysine. In the present study, N-succinimidyl-4-[(18)F]fluorobenzoate was used to modify N(epsilon)-(gamma-glutamyl)-L-lysine at each of its two alpha-amino groups, resulting in the 4-[(18)F]fluorobenzoylated derivatives, for which biodistribution, catabolism, and elimination were investigated in male Wistar rats. A significant different biochemical behavior of the two labelled isopeptides was observed in terms of in vitro stability, in vivo metabolism as well as biodistribution. The results suggest that the metabolic fate of isopeptides is likely to be dependent on how they are reabsorbed - free or peptide bound.

Biomass production from electricity using ammonia as an electron carrier in a reverse microbial fuel cell.

Directory of Open Access Journals (Sweden)

Wendell O Khunjar

Full Text Available The storage of renewable electrical energy within chemical bonds of biofuels and other chemicals is a route to decreasing petroleum usage. A critical challenge is the efficient transfer of electrons into a biological host that can covert this energy into high energy organic compounds. In this paper, we describe an approach whereby biomass is grown using energy obtained from a soluble mediator that is regenerated electrochemically. The net result is a separate-stage reverse microbial fuel cell (rMFC that fixes CO₂ into biomass using electrical energy. We selected ammonia as a low cost, abundant, safe, and soluble redox mediator that facilitated energy transfer to biomass. Nitrosomonas europaea, a chemolithoautotroph, was used as the biocatalyst due to its inherent capability to utilize ammonia as its sole energy source for growth. An electrochemical reactor was designed for the regeneration of ammonia from nitrite, and current efficiencies of 100% were achieved. Calculations indicated that overall bioproduction efficiency could approach 2.7±0.2% under optimal electrolysis conditions. The application of chemolithoautotrophy for industrial bioproduction has been largely unexplored, and results suggest that this and related rMFC platforms may enable biofuel and related biochemical production.

Microbial community composition during anaerobic mineralization of tert-butyl alcohol (TBA) in fuel-contaminated aquifer material.

Science.gov (United States)

Wei, Na; Finneran, Kevin T

2011-04-01

Anaerobic mineralization of tert-butyl alcohol (TBA) and methyl tert-butyl ether (MTBE) were studied in sediment incubations prepared with fuel-contaminated aquifer material. Microbial community compositions in all incubations were characterized by amplified ribosomal DNA restriction analysis (ARDRA). The aquifer material mineralized 42.3±9.9% of [U-(14)C]-TBA to 14CO2 without electron acceptor amendment. Fe(III), sulfate, and Fe(III) plus anthraquinone-2,6-disulfonate addition also promoted U-[14C]-TBA mineralization at levels similar to those of the unamended controls. Nitrate actually inhibited TBA mineralization relative to unamended controls. In contrast to TBA, [U-(14)C]-MTBE was not significantly mineralized in 400 days regardless of electron acceptor amendment. Microbial community analysis indicated that the abundance of one dominant clone group correlated closely with anaerobic TBA mineralization. The clone was phylogenetically distinct from known aerobic TBA-degrading microorganisms, Fe(III)- or sulfate-reducing bacteria. It was most closely associated with organisms belonging to the alphaproteobacteria. Microbial communities were different in MTBE and TBA amended incubations. Shannon indices and Simpson indices (statistical community comparison tools) both demonstrated that microbial community diversity decreased in incubations actively mineralizing TBA, with distinct "dominant" clones developing. These data contribute to our understanding of anaerobic microbial transformation of fuel oxygenates in contaminated aquifer material and the organisms that may catalyze the reactions.

Microbial activity in the marine deep biosphere: progress and prospects.

Science.gov (United States)

Orcutt, Beth N; Larowe, Douglas E; Biddle, Jennifer F; Colwell, Frederick S; Glazer, Brian T; Reese, Brandi Kiel; Kirkpatrick, John B; Lapham, Laura L; Mills, Heath J; Sylvan, Jason B; Wankel, Scott D; Wheat, C Geoff

2013-01-01

The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists-all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these "extreme" environments survive (or even thrive). Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) "theme team" on microbial activity (www.darkenergybiosphere.org).

Microbial Rechargeable Battery

NARCIS (Netherlands)

Molenaar, Sam D.; Mol, Annemerel R.; Sleutels, Tom H.J.A.; Heijne, Ter Annemiek; Buisman, Cees J.N.

2016-01-01

Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial

Dechlorinating ability of TCE-fed microcosms with different electron donors

International Nuclear Information System (INIS)

Panagiotakis, Iraklis; Mamais, Daniel; Pantazidou, Marina; Marneri, Matina; Parapouli, Maria; Hatziloukas, Efstathios; Tandoi, Valter

2007-01-01

The main objective of the work presented herein is to assess the effect of different electron donors (butyric acid and methanol) on the dechlorinating activity of two microbial cultures where active methanogenic populations are present, in an effort to evaluate the importance of the electron donor selection process. The ability of each anaerobic culture to dechlorinate TCE, when enriched with either butyric acid or methanol, was verified based on the results of gas chromatography. In addition, the fluorescent in situ hybridization (FISH) and the polymerase chain reaction (PCR) methods gave positive results for the presence of Dehalococcoides spp. According to results of the batch tests conducted in this study, it appears that the selection of the electron donor for stimulating TCE dechlorination depends on microbial culture composition; therefore, the decision on the appropriate electron donor should be based on site-specific microcosm studies

Microbial fuel cells for clogging assessment in constructed wetlands

Energy Technology Data Exchange (ETDEWEB)

Corbella, Clara; García, Joan; Puigagut, Jaume, E-mail: jaume.puigagut@upc.edu

2016-11-01

Clogging in HSSF CW may result in a reduction of system's life-span or treatment efficiency. Current available techniques to assess the degree of clogging in HSSF CW are time consuming and cannot be applied on a continuous basis. Main objective of this work was to assess the potential applicability of microbial fuel cells for continuous clogging assessment in HSSF CW. To this aim, two replicates of a membrane-less microbial fuel cell (MFC) were built up and operated under laboratory conditions for five weeks. The MFC anode was gravel-based to simulate the filter media of HSSF CW. MFC were weekly loaded with sludge that had been accumulating for several years in a pilot HSSF CW treating domestic wastewater. Sludge loading ranged from ca. 20 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the beginning of the study period up to ca. 250 kg TS·m{sup −} {sup 3} CW·year{sup −} {sup 1} at the end of the study period. Sludge loading applied resulted in sludge accumulated within the MFC equivalent to a clogging degree ranging from 0.2 years (ca. 0.5 kg TS·m{sup –3}CW) to ca. 5 years (ca. 10 kg TS·m{sup –3}CW). Results showed that the electric charge was negatively correlated to the amount of sludge accumulated (degree of clogging). Electron transference (expressed as electric charge) almost ceased when accumulated sludge within the MFC was equivalent to ca. 5 years of clogging (ca. 10 kg TS·m{sup –3}CW). This result suggests that, although longer study periods under more realistic conditions shall be further performed, HSSF CW operated as a MFC has great potential for clogging assessment. - Highlights: • Microbial fuel cells are used as tool for clogging assessment in constructed wetlands. • Microbial fuel cells were loaded with sludge from constructed wetlands. • Sludge retained within the systems simulated a clogging time ranging from 0.2 to ca. 5 years. • Electrons transferred decreased potentially as function of sludge loading. �

PCE dechlorination by non-Dehalococcoides in a microbial electrochemical system.

Science.gov (United States)

Yu, Jaecheul; Park, Younghyun; Nguyen, Van Khanh; Lee, Taeho

2016-08-01

The bioremediation of tetrachloroethene (perchloroethene; PCE) contaminated sites generally requires a supply of some fermentable organic substrates as an electron donor. On the other hand, organic substrates can induce the massive growth of microorganisms around the injection wells, which can foul the contaminated subsurface environment. In this study, PCE dechlorination to ethene was performed in a microbial electrochemical system (MES) using the electrode (a cathode polarized at -500 mV vs. standard hydrogen electrode) as the electron donor. Denaturing gel gradient electrophoresis and pyrosequencing revealed a variety of non-Dehalococcoides bacteria dominant in MES, such as Acinetobacter sp. (25.7 % for AS1 in suspension of M3), Rhodopseudomonas sp. (10.5 % for AE1 and 10.1 % for AE2 in anodic biofilm of M3), Pseudomonas aeruginosa (22.4 % for BS1 in suspension of M4), and Enterobacter sp. (21.7 % for BE1 in anodic biofilm of M4) which are capable of electron transfer, hydrogen production and dechlorination. The Dehalococcoides group, however, was not detected in this system. Therefore, these results suggest that a range of bacterial species outside the Dehalococcoides can play an important role in the microbial electrochemical dechlorination process, which may lead to innovative bioremediation technology.

Transglutaminase 2 is needed for the formation of an efficient phagocyte portal in macrophages engulfing apoptotic cells.

Science.gov (United States)

Tóth, Beáta; Garabuczi, Eva; Sarang, Zsolt; Vereb, György; Vámosi, György; Aeschlimann, Daniel; Blaskó, Bernadett; Bécsi, Bálint; Erdõdi, Ferenc; Lacy-Hulbert, Adam; Zhang, Ailiang; Falasca, Laura; Birge, Raymond B; Balajthy, Zoltán; Melino, Gerry; Fésüs, László; Szondy, Zsuzsa

2009-02-15

Transglutaminase 2 (TG2), a protein cross-linking enzyme with many additional biological functions, acts as coreceptor for integrin beta(3). We have previously shown that TG2(-/-) mice develop an age-dependent autoimmunity due to defective in vivo clearance of apoptotic cells. Here we report that TG2 on the cell surface and in guanine nucleotide-bound form promotes phagocytosis. Besides being a binding partner for integrin beta(3), a receptor known to mediate the uptake of apoptotic cells via activating Rac1, we also show that TG2 binds MFG-E8 (milk fat globulin EGF factor 8), a protein known to bridge integrin beta(3) to apoptotic cells. Finally, we report that in wild-type macrophages one or two engulfing portals are formed during phagocytosis of apoptotic cells that are characterized by accumulation of integrin beta(3) and Rac1. In the absence of TG2, integrin beta(3) cannot properly recognize the apoptotic cells, is not accumulated in the phagocytic cup, and its signaling is impaired. As a result, the formation of the engulfing portals, as well as the portals formed, is much less efficient. We propose that TG2 has a novel function to stabilize efficient phagocytic portals.

Structure of the Dispase Autolysis-inducing Protein from Streptomyces mobaraensis and Glutamine Cross-linking Sites for Transglutaminase.

Science.gov (United States)

Fiebig, David; Schmelz, Stefan; Zindel, Stephan; Ehret, Vera; Beck, Jan; Ebenig, Aileen; Ehret, Marina; Fröls, Sabrina; Pfeifer, Felicitas; Kolmar, Harald; Fuchsbauer, Hans-Lothar; Scrima, Andrea

2016-09-23

Transglutaminase from Streptomyces mobaraensis (MTG) is an important enzyme for cross-linking and modifying proteins. An intrinsic substrate of MTG is the dispase autolysis-inducing protein (DAIP). The amino acid sequence of DAIP contains 5 potential glutamines and 10 lysines for MTG-mediated cross-linking. The aim of the study was to determine the structure and glutamine cross-linking sites of the first physiological MTG substrate. A production procedure was established in Escherichia coli BL21 (DE3) to obtain high yields of recombinant DAIP. DAIP variants were prepared by replacing four of five glutamines for asparagines in various combinations via site-directed mutagenesis. Incorporation of biotin cadaverine revealed a preference of MTG for the DAIP glutamines in the order of Gln-39 ≫ Gln-298 > Gln-345 ∼ Gln-65 ≫ Gln-144. In the structure of DAIP the preferred glutamines do cluster at the top of the seven-bladed β-propeller. This suggests a targeted cross-linking of DAIP by MTG that may occur after self-assembly in the bacterial cell wall. Based on our biochemical and structural data of the first physiological MTG substrate, we further provide novel insight into determinants of MTG-mediated modification, specificity, and efficiency. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Application of 13C and 15N stable isotope probing to characterize RDX degrading microbial communities under different electron-accepting conditions

International Nuclear Information System (INIS)

Cho, Kun-Ching; Lee, Do Gyun; Fuller, Mark E.; Hatzinger, Paul B.; Condee, Charles W.; Chu, Kung-Hui

2015-01-01

Highlights: • SIP characterized RDX-degrading communities under different e-accepting conditions. • Dominant RDX degradation pathways differed under different e-accepting conditions. • More complete detoxification of RDX occurred under methanogenic and sulfate-reducing conditions than under manganese(IV) and iron(III)-reducing conditions. - Abstract: This study identified microorganisms capable of using the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) or its metabolites as carbon and/or nitrogen sources under different electron-accepting conditions using 13 C and 15 N stable isotope probing (SIP). Mesocosms were constructed using groundwater and aquifer solids from an RDX-contaminated aquifer. The mesocosms received succinate as a carbon source and one of four electron acceptors (nitrate, manganese(IV), iron(III), or sulfate) or no additional electron acceptor (to stimulate methanogenesis). When RDX degradation was observed, subsamples from each mesocosm were removed and amended with 13 C 3 - or ring- 15 N 3 -, nitro- 15 N 3 -, or fully-labeled 15 N 6 -RDX, followed by additional incubation and isolation of labeled nucleic acids. A total of fifteen 16S rRNA sequences, clustering in α- and γ-Proteobacteria, Clostridia, and Actinobacteria, were detected in the 13 C-DNA fractions. A total of twenty seven sequences were derived from different 15 N-DNA fractions, with the sequences clustered in α- and γ-Proteobacteria, and Clostridia. Interestingly, sequences identified as Desulfosporosinus sp. (in the Clostridia) were not only observed to incorporate the labeled 13 C or 15 N from labeled RDX, but also were detected under each of the different electron-accepting conditions. The data suggest that 13 C- and 15 N-SIP can be used to characterize microbial communities involved in RDX biodegradation, and that the dominant pathway of RDX biodegradation may differ under different electron-accepting conditions

Microbial biosensors

International Nuclear Information System (INIS)

Le Yu; Chen, Wilfred; Mulchandani, Ashok

2006-01-01

A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

Childhood microbial keratitis

Directory of Open Access Journals (Sweden)

Abdullah G Al Otaibi

2012-01-01

Conclusion: Children with suspected microbial keratitis require comprehensive evaluation and management. Early recognition, identifying the predisposing factors and etiological microbial organisms, and instituting appropriate treatment measures have a crucial role in outcome. Ocular trauma was the leading cause of childhood microbial keratitis in our study.

Use of a Burkholderia cenocepacia ABTS Oxidizer in a Microbial Fuel Cell

Science.gov (United States)

Microbial fuel cells (MFCs) often use biological processes to generate electrons from organic material contained in the anode chamber and abiotic processes employing atmospheric oxygen as the oxidant in the cathode chamber. This study investigated the accumulation of an oxidant in bacterial cultures...

Dynamics of Molecular Hydrogen in Hypersaline Microbial Mars

Science.gov (United States)

Hoehler, Tori M.; Bebout, Brad M.; Visscher, Pieter T.; DesMarais, David J.; DeVincenzi, Donald L. (Technical Monitor)

2000-01-01

Early Earth microbial communities that centered around the anaerobic decomposition of organic molecular hydrogen as a carrier of electrons, regulator of energy metabolism, and facilitator of syntroph'c microbial interactions. The advent of oxygenic photosynthetic organisms added a highly dynamic and potentially dominant term to the hydrogen economy of these communities. We have examined the daily variations of hydrogen concentrations in cyanobacteria-dominated microbial mats from hypersaline ponds in Baja California Sur, Mexico. These mats bring together phototrophic and anaerobic bacteria (along with virtually all other trophic groups) in a spatially ordered and chemically dynamic matrix that provides a good analog for early Earth microbial ecosystems. Hydrogen concentrations in the photic zone of the mat can be three orders of magnitude or more higher than in the photic zone, which are, in turn, an order of magnitude higher than in the unconsolidated sediments underlying the mat community. Within the photic zone, hydrogen concentrations can fluctuate dramatically during the diel (24 hour day-night) cycle, ranging from less than 0.001% during the day to nearly 10% at night. The resultant nighttime flux of hydrogen from the mat to the environment was up to 17% of the daytime oxygen flux. The daily pattern observed is highly dependent on cyanobacterial species composition within the mat, with Lyngbya-dominated systems having a much greater dynamic range than those dominated by Microcoleus; this may relate largely to differing degrees of nitrogen-fixing and fermentative activity in the two mats. The greatest H2 concentrations and fluxes were observed in the absence of oxygen, suggesting an important potential feedback control in the context of the evolution of atmospheric composition. The impact of adding this highly dynamic photosynthetic term to the hydrogen economy of early microbial ecosystems must have been substantial. From an evolutionary standpoint, the H2

Microbial Biosynthesis of Silver Nanoparticles in Different Culture Media.

Science.gov (United States)

Luo, Ke; Jung, Samuel; Park, Kyu-Hwan; Kim, Young-Rok

2018-01-31

Microbial biosynthesis of metal nanoparticles has been extensively studied for the applications in biomedical sciences and engineering. However, the mechanism for their synthesis through microorganism is not completely understood. In this study, several culture media were investigated for their roles in the microbial biosynthesis of silver nanoparticles (AgNPs). The size and morphology of the synthesized AgNPs were analyzed by UV-vis spectroscopy, Fourier-transform-infrared (FT-IR), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The results demonstrated that nutrient broth (NB) and Mueller-Hinton broth (MHB) among tested media effectively reduced silver ions to form AgNPs with different particle size and shape. Although the involved microorganism enhanced the reduction of silver ions, the size and shape of the particles were shown to mainly depend on the culture media. Our findings suggest that the growth media of bacterial culture play an important role in the synthesis of metallic nanoparticles with regard to their size and shape. We believe our findings would provide useful information for further exploration of microbial biosynthesis of AgNPs and their biomedical applications.

Assessment of Microbial Fuel Cell Configurations and Power Densities

KAUST Repository

Logan, Bruce E.

2015-07-30

Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

Assessment of Microbial Fuel Cell Configurations and Power Densities

KAUST Repository

Logan, Bruce E.; Wallack, Maxwell J; Kim, Kyoung-Yeol; He, Weihua; Feng, Yujie; Saikaly, Pascal

2015-01-01

Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

Brazilian kefir: structure, microbial communities and chemical composition

Directory of Open Access Journals (Sweden)

Karina Teixeira Magalhães

2011-06-01

Full Text Available Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5% were the major isolated group identified, followed by yeasts (30.6% and acetic acid bacteria (8.9%. Lactobacillus paracasei (89 isolates, Lactobacillus parabuchneri (41 isolates, Lactobacillus casei (32 isolates, Lactobacillus kefiri (31 isolates, Lactococcus lactis (24 isolates, Acetobacter lovaniensis (32 isolates, Kluyveromyces lactis (31 isolates, Kazachstania aerobia (23 isolates, Saccharomyces cerevisiae (41 isolates and Lachancea meyersii (15 isolates were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml.

Brazilian kefir: structure, microbial communities and chemical composition

Science.gov (United States)

Magalhães, Karina Teixeira; de Melo Pereira, Gilberto Vinícius; Campos, Cássia Roberta; Dragone, Giuliano; Schwan, Rosane Freitas

2011-01-01

Microbial ecology and chemical composition of Brazilian kefir beverage was performed. The microorganisms associated with Brazilian kefir were investigated using a combination of phenotypic and genotypic methods. A total of 359 microbial isolates were identified. Lactic acid bacteria (60.5%) were the major isolated group identified, followed by yeasts (30.6%) and acetic acid bacteria (8.9%). Lactobacillus paracasei (89 isolates), Lactobacillus parabuchneri (41 isolates), Lactobacillus casei (32 isolates), Lactobacillus kefiri (31 isolates), Lactococcus lactis (24 isolates), Acetobacter lovaniensis (32 isolates), Kluyveromyces lactis (31 isolates), Kazachstania aerobia (23 isolates), Saccharomyces cerevisiae (41 isolates) and Lachancea meyersii (15 isolates) were the microbial species isolated. Scanning electron microscopy showed that the microbiota was dominated by bacilli (short and curved long) cells growing in close association with lemon-shaped yeasts cells. During the 24 h of fermentation, the protein content increased, while lactose and fat content decreased. The concentration of lactic acid ranged from 1.4 to 17.4 mg/ml, and that of acetic acid increased from 2.1 to 2.73 mg/ml. The production of ethanol was limited, reaching a final mean value of 0.5 mg/ml. PMID:24031681

Electron-beam induced structural and function change of microbial peroxiredoxin

Energy Technology Data Exchange (ETDEWEB)

Hong, S. H.; An, B. C.; Lee, S. S.; Lee, E. M.; Chung, B. Y. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2012-03-15

Pseudomonas aerogenes peroxiredoxin (PaPrx) has dual functions acting as thioredoxin (Trx)-dependent peroxidase and molecular chaperone. The function of PaPrx is controlled by its structural status. In this study, we examined the effect of electron beam on structural modification related to chaperone activity. When irradiated electron beam at 1 kGy, the structural and functional changes of PaPrx were initiated. The enhanced chaperone activity was increased about 3- 40 4-fold at 2 kGy compared with non-irradiated, while the peroxidase activity was decreased. We also investigated the influence of the electron beam on protein physical property factors such as hydrophobicity and secondary structure. The exposure of hydrophobic domains reached a peak at 2 kGy of electron beam and then dose-dependently decreased with increasing electron beam irradiation. In addition, the electron beam irradiated PaPrx significantly increased exposure of {beta}-sheet and random coil elements on the protein surface whereas exposure of {alpha}-helix and turn elements was decreased. Our results suggest that highly enhanced chaperone activity could be applied to use in bio-engineering system and various industrial applications.

Electron-beam induced structural and function change of microbial peroxiredoxin

International Nuclear Information System (INIS)

Hong, S. H.; An, B. C.; Lee, S. S.; Lee, E. M.; Chung, B. Y.

2012-01-01

Pseudomonas aerogenes peroxiredoxin (PaPrx) has dual functions acting as thioredoxin (Trx)-dependent peroxidase and molecular chaperone. The function of PaPrx is controlled by its structural status. In this study, we examined the effect of electron beam on structural modification related to chaperone activity. When irradiated electron beam at 1 kGy, the structural and functional changes of PaPrx were initiated. The enhanced chaperone activity was increased about 3- 40 4-fold at 2 kGy compared with non-irradiated, while the peroxidase activity was decreased. We also investigated the influence of the electron beam on protein physical property factors such as hydrophobicity and secondary structure. The exposure of hydrophobic domains reached a peak at 2 kGy of electron beam and then dose-dependently decreased with increasing electron beam irradiation. In addition, the electron beam irradiated PaPrx significantly increased exposure of β-sheet and random coil elements on the protein surface whereas exposure of α-helix and turn elements was decreased. Our results suggest that highly enhanced chaperone activity could be applied to use in bio-engineering system and various industrial applications

DOTA-Functionalized Polylysine: A High Number of DOTA Chelates Positively Influences the Biodistribution of Enzymatic Conjugated Anti-Tumor Antibody chCE7agl.

OpenAIRE

Grünberg Jürgen; Jeger Simone; Sarko Dikran; Dennler Patrick; Zimmermann Kurt; Mier Walter; Schibli Roger

2013-01-01

Site-specific enzymatic reactions with microbial transglutaminase (mTGase) lead to a homogenous species of immunoconjugates with a defined ligand/antibody ratio. In the present study, we have investigated the influence of different numbers of 1,4,7,10-tetraazacyclododecane-N-N'-N''-N'''-tetraacetic acid (DOTA) chelats coupled to a decalysine backbone on the in vivo behavior of the chimeric monoclonal anti-L1CAM antibody chCE7agl. The enzymatic conjugation of (DOTA)1-decalysine, (DOTA)3-decaly...

Microbial Effects in Promoting the Smectite to Illite Reaction: Role of Organic Matter Intercalated in the Interlayer

Science.gov (United States)

2007-01-01

American Mineralogist, Volume 92. pages 1401-1410, 2007 Microbial effects in promoting the smectite to illite reaction: Role of organic matter...rich smectite (non- tronile, NAu-2). The illitization of these intercalated smectites as induced by microbial reduction of structural Fe" was...transmission electron microscopy did not detect any discrete illite, although illite/ smectite mixed layer or high charge smectite phases were observed. In

Visualizing Microbial Biogeochemistry: NanoSIMS and Stable Isotope Probing (Invited)

Science.gov (United States)

Pett-Ridge, J.; Weber, P. K.

2009-12-01

Linking phylogenetic information to function in microbial communities is a key challenge for microbial ecology. Isotope-labeling experiments provide a useful means to investigate the ecophysiology of microbial populations and cells in the environment and allow measurement of nutrient transfers between cell types, symbionts and consortia. The combination of Nano-Secondary Ion Mass Spectrometry (NanoSIMS) analysis, in situ labeling and high resolution microscopy allows isotopic analysis to be linked to phylogeny and morphology and holds great promise for fine-scale studies of microbial systems. In NanoSIMS analysis, samples are sputtered with an energetic primary beam (Cs+, O-) liberating secondary ions that are separated by the mass spectrometer and detected in a suite of electron multipliers. Five isotopic species may be analyzed concurrently with spatial resolution as fine as 50nm. A high sensitivity isotope ratio ‘map’ can then be generated for the analyzed area. NanoSIMS images of 13C, 15N and Mo (a nitrogenase co-factor) localization in diazotrophic cyanobacteria show how cells differentially allocate resources within filaments and allow calculation of nutrient uptake rates on a cell by cell basis. Images of AM fungal hyphae-root and cyanobacteria-rhizobia associations indicate the mobilization and sharing (stealing?) of newly fixed C and N. In a related technique, “El-FISH”, stable isotope labeled biomass is probed with oligonucleotide-elemental labels and then imaged by NanoSIMS. In microbial consortia and cyanobacterial mats, this technique helps link microbial structure and function simultaneously even in systems with unknown and uncultivated microbes. Finally, the combination of re-engineered universal 16S oligonucleotide microarrays with NanoSIMS analyses may allow microbial identity to be linked to functional roles in complex systems such as mats and cellulose degrading hindgut communities. These newly developed methods provide correlated

Quantum dots conjugated zinc oxide nanosheets: Impeder of microbial growth and biofilm

Science.gov (United States)

Patil, Rajendra; Gholap, Haribhau; Warule, Sambhaji; Banpurkar, Arun; Kulkarni, Gauri; Gade, Wasudeo

2015-01-01

The grieving problem of the 21st century has been the antimicrobial resistance in pathogenic microorganisms to conventional antibiotics. Therefore, developments of novel antibacterial materials which effectively inhibit or kill such resistant microorganisms have become the need of the hour. In the present study, we communicate the synthesis of quantum dots conjugated zinc oxide nanostructures (ZnO/CdTe) as an impeder of microbial growth and biofilm. The as-synthesized nanostructures were characterized by X-ray diffraction, ultraviolet-visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and high resolution transmission electron microscopy. The growth impedance property of ZnO and ZnO/CdTe on Gram positive organism, Bacillus subtilis NCIM 2063 and Gram negative, Escherichia coli NCIM 2931 and biofilm impedance activity in Pseudomonas aeruginosa O1 was found to occur due to photocatalytical action on the cell biofilm surfaces. The impedance in microbial growth and biofilm formation was further supported by ruptured appearances of cells and dettrered biofilm under field emission scanning electron and confocal laser scanning microscope. The ZnO/CdTe nanostructures array synthesized by hydrothermal method has an advantage of low growth temperature, and opportunity to fabricate inexpensive material for nano-biotechnological applications.

[Fibers as carriers of microbial particles].

Science.gov (United States)

Górny, Rafał L; Ławniczek-Wałczyk, Anna; Stobnicka, Agata; Gołofit-Szymczak, Małgorzata; Cyprowski, Marcin

2015-01-01

The aim of the study was to assess the ability of natural, synthetic and semi-synthetic fibers to transport microbial particles. The simultaneously settled dust and aerosol sampling was carried out in 3 industrial facilities processing natural (cotton, silk, flax, hemp), synthetic (polyamide, polyester, polyacrylonitrile, polypropylene) and semi-synthetic (viscose) fibrous materials; 2 stables where horses and sheep were bred; 4 homes where dogs or cats were kept and 1 zoo lion pavilion. All samples were laboratory analyzed for their microbiological purity. The isolated strains were qualitatively identified. To identify the structure and arrangement of fibers that may support transport of microbial particles, a scanning electron microscopy analysis was performed. Both settled and airborne fibers transported analogous microorganisms. All synthetic, semi-synthetic and silk fibers, present as separated threads with smooth surface, were free from microbial contamination. Natural fibers with loose packing and rough surface (e.g., wool, horse hair), sheaf packing and septated surface (e.g., flax, hemp) or present as twisted ribbons with corrugated surface (cotton) were able to carry up to 9×10(5) cfu/g aerobic bacteria, 3.4×10(4) cfu/g anaerobic bacteria and 6.3×10(4) cfu/g of fungi, including pathogenic strains classified by Directive 2000/54/EC in hazard group 2. As plant and animal fibers are contaminated with a significant number of microorganisms, including pathogens, all of them should be mechanically eliminated from the environment. In factories, if the manufacturing process allows, they should be replaced by synthetic or semi-synthetic fibers. To avoid unwanted exposure to harmful microbial agents on fibers, the containment measures that efficiently limit their presence and dissemination in both occupational and non-occupational environments should be introduced. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Fibers as carriers of microbial particles

Directory of Open Access Journals (Sweden)

Rafał L. Górny

2015-08-01

Full Text Available Background: The aim of the study was to assess the ability of natural, synthetic and semi-synthetic fibers to transport microbial particles. Material and Methods: The simultaneously settled dust and aerosol sampling was carried out in 3 industrial facilities processing natural (cotton, silk, flax, hemp, synthetic (polyamide, polyester, polyacrylonitrile, polypropylene and semi-synthetic (viscose fibrous materials; 2 stables where horses and sheep were bred; 4 homes where dogs or cats were kept and 1 zoo lion pavilion. All samples were laboratory analyzed for their microbiological purity. The isolated strains were qualitatively identified. To identify the structure and arrangement of fibers that may support transport of microbial particles, a scanning electron microscopy analysis was performed. Results: Both settled and airborne fibers transported analogous microorganisms. All synthetic, semi-synthetic and silk fibers, present as separated threads with smooth surface, were free from microbial contamination. Natural fibers with loose packing and rough surface (e.g., wool, horse hair, sheaf packing and septated surface (e.g., flax, hemp or present as twisted ribbons with corrugated surface (cotton were able to carry up to 9×105 cfu/g aerobic bacteria, 3.4×104 cfu/g anaerobic bacteria and 6.3×104 cfu/g of fungi, including pathogenic strains classified by Directive 2000/54/EC in hazard group 2. Conclusions: As plant and animal fibers are contaminated with a significant number of microorganisms, including pathogens, all of them should be mechanically eliminated from the environment. In factories, if the manufacturing process allows, they should be replaced by synthetic or semi-synthetic fibers. To avoid unwanted exposure to harmful microbial agents on fibers, the containment measures that efficiently limit their presence and dissemination in both occupational and non-occupational environments should be introduced. Med Pr 2015;66(4:511–523

Microbiological decontamination of Spirulina Platensis and green coffee using accelerated electron beams

International Nuclear Information System (INIS)

Nemtanu, Monica R.; Brasoveanu, Mirela; Minea, R.; Mitru, Ecaterina; Grecu, Maria Nicoleta; Albulescu, Mihaela

2006-01-01

Biological raw materials can be contaminated with microorganisms and to make them suitable for commercialization, the quality relative to microbial content is necessary to be achieved. Irradiation is a decontamination method for numerous foodstuffs, being a feasible, very effective and environment friendly procedure. The aim of the paper is to evaluate the possibility to apply the electron beam treatment on Spirulina Platensis and green coffee for biological decontamination. The cyanobacterium Spirulina and green coffee have been irradiated with electron beams up to 40 kGy. To determine the microbial load, antioxidant activity, and rheological behaviour the techniques of electron paramagnetic resonance (EPR) and absorption spectroscopy have been applied. The results showed that accelerated electron beams could be efficient to decontaminate Spirulina as well as green coffee without significant changes in their properties. (authors)

Microbial deterioration of Mayan stone buildings at Uxmal, Yucatan, Mexico

International Nuclear Information System (INIS)

Ortega-Morales, O.; Guezennec, J.; Hernandez D, G.; Jozsa, P.; Sand, W.; Crassous, P.

1998-01-01

The microbial communities associated to Uxmal Mayan monuments (Yucatan, Mexico) and their role in stone deterioration were preliminary characterized by chemical, biochemical, microbiological, microscopical and surface analysis methods under two climatic seasons (1997). The organic matter and organic carbon and nitrogen were in the range of those reported for other stone buildings, indicating that oligo trophic conditions prevail at Uxmal. Quantitative differences in microbial biomass was higher at indoor section were the organic matter content was the highest and micro-environmental conditions (availability of water and protection to direct sunlight) are more suitable for microbial growth. The microbiological analysis underestimated the microbial biomass, as revealed by biochemical approaches. Nitrate and nitrite-oxidizing, metilotrophic and heterotrophic bacteria and fungi were detected in most surfaces. The heterotrophic bacteria were the most abundant microbial group (microbiological data). However, the chlorophyll profiles and Scanning Electron Microscopy showed that the microalgae are the most abundant colonizers in Uxmal stone buildings. EDAX analysis showed that the most surfaces were covered by an organic layer (cells and exo polymers). Gypsum was found in few samples. The large photo trophic biomass seems to play a role in stone bio deterioration by supporting growth of heterotrophic microorganisms (bacteria and fungi) which are known to produce organic acids leading to calcite dissolution and cations chelation. Further studies are being carried out in order to determine the role of exo polysaccharides which are thought to play a role in chemical degradation of limestone substrates in Uxmal. (Author)

Effect of long-term fertilization on humic redox mediators in multiple microbial redox reactions.

Science.gov (United States)

Guo, Peng; Zhang, Chunfang; Wang, Yi; Yu, Xinwei; Zhang, Zhichao; Zhang, Dongdong

2018-03-01

This study investigated the effects of different long-term fertilizations on humic substances (HSs), humic acids (HAs) and humins, functioning as redox mediators for various microbial redox biotransformations, including 2,2',4,4',5,5'- hexachlorobiphenyl (PCB 153 ) dechlorination, dissimilatory iron reduction, and nitrate reduction, and their electron-mediating natures. The redox activity of HSs for various microbial redox metabolisms was substantially enhanced by long-term application of organic fertilizer (pig manure). As a redox mediator, only humin extracted from soils with organic fertilizer amendment (OF-HM) maintained microbial PCB 153 dechlorination activity (1.03 μM PCB 153 removal), and corresponding HA (OF-HA) most effectively enhanced iron reduction and nitrate reduction by Shewanella putrefaciens. Electrochemical analysis confirmed the enhancement of their electron transfer capacity and redox properties. Fourier transform infrared analysis showed that C=C and C=O bonds, and carboxylic or phenolic groups in HSs might be the redox functional groups affected by fertilization. This research enhances our understanding of the influence of anthropogenic fertility on the biogeochemical cycling of elements and in situ remediation ability in agroecosystems through microorganisms' metabolisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Life in the "plastisphere": microbial communities on plastic marine debris.

Science.gov (United States)

Zettler, Erik R; Mincer, Tracy J; Amaral-Zettler, Linda A

2013-07-02

Plastics are the most abundant form of marine debris, with global production rising and documented impacts in some marine environments, but the influence of plastic on open ocean ecosystems is poorly understood, particularly for microbial communities. Plastic marine debris (PMD) collected at multiple locations in the North Atlantic was analyzed with scanning electron microscopy (SEM) and next-generation sequencing to characterize the attached microbial communities. We unveiled a diverse microbial community of heterotrophs, autotrophs, predators, and symbionts, a community we refer to as the "Plastisphere". Pits visualized in the PMD surface conformed to bacterial shapes suggesting active hydrolysis of the hydrocarbon polymer. Small-subunit rRNA gene surveys identified several hydrocarbon-degrading bacteria, supporting the possibility that microbes play a role in degrading PMD. Some Plastisphere members may be opportunistic pathogens (the authors, unpublished data) such as specific members of the genus Vibrio that dominated one of our plastic samples. Plastisphere communities are distinct from surrounding surface water, implying that plastic serves as a novel ecological habitat in the open ocean. Plastic has a longer half-life than most natural floating marine substrates, and a hydrophobic surface that promotes microbial colonization and biofilm formation, differing from autochthonous substrates in the upper layers of the ocean.

Microbial activity in the marine deep biosphere: Progress and prospects

Directory of Open Access Journals (Sweden)

Beth N Orcutt

2013-07-01

Full Text Available The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists – all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these "extreme" environments survive (or even thrive. Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI "theme team" on microbial activity (www.darkenergybiosphere.org.

Microbial activity in the marine deep biosphere: progress and prospects

Science.gov (United States)

Orcutt, Beth N.; LaRowe, Douglas E.; Biddle, Jennifer F.; Colwell, Frederick S.; Glazer, Brian T.; Reese, Brandi Kiel; Kirkpatrick, John B.; Lapham, Laura L.; Mills, Heath J.; Sylvan, Jason B.; Wankel, Scott D.; Wheat, C. Geoff

2013-01-01

The vast marine deep biosphere consists of microbial habitats within sediment, pore waters, upper basaltic crust and the fluids that circulate throughout it. A wide range of temperature, pressure, pH, and electron donor and acceptor conditions exists—all of which can combine to affect carbon and nutrient cycling and result in gradients on spatial scales ranging from millimeters to kilometers. Diverse and mostly uncharacterized microorganisms live in these habitats, and potentially play a role in mediating global scale biogeochemical processes. Quantifying the rates at which microbial activity in the subsurface occurs is a challenging endeavor, yet developing an understanding of these rates is essential to determine the impact of subsurface life on Earth's global biogeochemical cycles, and for understanding how microorganisms in these “extreme” environments survive (or even thrive). Here, we synthesize recent advances and discoveries pertaining to microbial activity in the marine deep subsurface, and we highlight topics about which there is still little understanding and suggest potential paths forward to address them. This publication is the result of a workshop held in August 2012 by the NSF-funded Center for Dark Energy Biosphere Investigations (C-DEBI) “theme team” on microbial activity (www.darkenergybiosphere.org). PMID:23874326

Facile in-situ fabrication of graphene/riboflavin electrode for microbial fuel cells

International Nuclear Information System (INIS)

Wang, Qian-Qian; Wu, Xia-Yuan; Yu, Yang-Yang; Sun, De-Zhen; Jia, Hong-Hua; Yong, Yang-Chun

2017-01-01

A novel graphene/riboflavin (RF) composite electrode was developed and its potential application as microbial fuel cell (MFC) anode was demonstrated. Graphene layers were first grown on the surface of graphite electrode by a one-step in-situ electrochemical exfoliation approach. Then, noncovalent functionalization of the graphene layers with RF was achieved by a simple spontaneous adsorption process. The graphene/RF electrode was extensively characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, Raman analysis, and cyclic voltammetry analysis. Remarkably, when applied as the anode of Shewanella oneidensis MR-1 inoculated MFCs, the graphene/RF electrode significantly decreased charge transfer over-potential and enhanced cell attachment, which in turn delivered about 5.3- and 2.5-fold higher power output, when compared with that produced by the bare graphite paper electrode and graphene electrode, respectively. These results demonstrated that electron shuttle immobilization on the electrode surface could be a promising and practical strategy for improving the performance of microbial electrochemical systems.

Combined Effects of Nutrient and Pesticide Management on Soil Microbial Activity in Hybrid Rice Double Annual Cropping System

Institute of Scientific and Technical Information of China (English)

XIEXiao-mei; LIAOMin; LIUWei-ping; SusanneKLOSE

2004-01-01

Combined effects on soil microbial activity of nutrient and pesticide management in hybrid rice double annual cropping system were studied. Results of field experiment demonstrated significant changes in soil microbial biomass phospholipid contents,abundance of heterotrophic bacteria and proteolytic bacteria, electron transport system (ETS)/dehydrogenase activity, soil protein contents under different management practices and at various growth stages. Marked depletions in the soil microbial biomass phospholipid contents were found with the advancement of crop growth stages, while the incorporation of fertilizers and/or pesticides also induced slight changes, and the lowest microbial biomass phospholipid content was found with pesticides application alone. A decline in the bacterial abundance of heterotrophic bacteria and proteolytic bacteria was observed during the continuance of crop growth, while the lowest abundance of heterotrophic bacteria and proteolyrJc bacteria was found with pesticides application alone, which coincided with the decline of soil microbial biomass. A consistent increase in the electron transport svstem activit), was measured during the different crop growth stages of rice. The use of fertilizers (NPK) alone or combined with pesticides increased it, while a decline was noticed with pesticides application alone as compared with the control.The soil protein content was found to be relatively stable with fertilizers and/or pesticides application at various growth stages in both crops undertaken, but notable changes were detected at different growrh stages

Combined Effects of Nutrient and Pesticide Management on Soil Microbial Activity in Hybrid Rice Double Annual Cropping System

Institute of Scientific and Technical Information of China (English)

XIE Xiao-mei; LIAO Min; LIU Wei-ping; Susanne KLOSE

2004-01-01

Combined effects on soil microbial activity of nutrient and pesticide management in hybrid rice double annual cropping system were studied. Results of field experiment demonstrated significant changes in soil microbial biomass phospholipid contents,abundance of heterotrophic bacteria and proteolytic bacteria, electron transport system (ETS)/dehydrogenase activity, soil protein contents under different management practices and at various growth stages. Marked depletions in the soil microbial biomass phospholipid contents were found with the advancement of crop growth stages, while the incorporation of fertilizers and/or pesticides also induced slight changes, and the lowest microbial biomass phospholipid content was found with pesticides application alone. A decline in the bacterial abundance of heterotrophic bacteria and proteolytic bacteria was observed during the continuance of crop growth, while the lowest abundance of heterotrophic bacteria and proteolytic bacteria was found with pesticides application alone, which coincided with the decline of soil microbial biomass. A consistent increase in the electron transport system activity was measured during the different crop growth stages of rice. The use of fertilizers (NPK) alone or combined with pesticides increased it, while a decline was noticed with pesticides application alone as compared with the control.The soil protein content was found to be relatively stable with fertilizers and/or pesticides application at various growth stages in both crops undertaken, but notable changes were detected at different growth stages.

Proceedings of the 8. International Symposium on Microbial Ecology : microbial biosystems : new frontiers

International Nuclear Information System (INIS)

Bell, C.R.; Brylinsky, M.; Johnson-Green, P.

2000-01-01

A wide range of disciplines were presented at this conference which reflected the importance of microbial ecology and provided an understanding of the factors that determine the growth and activities of microorganisms. The conference attracted 1444 delegates from 54 countries. The research emerging from the rapidly expanding frontier of microbial ecosystems was presented in 62 oral presentation and 817 poster presentations. The two volumes of these proceedings presented a total of 27 areas in microbial ecology, some of which included terrestrial biosystems, aquatic, estuarine, surface and subsurface microbial ecology. Other topics included bioremediation, microbial ecology in industry and microbial ecology of oil fields. Some of the papers highlighted the research that is underway to determine the feasibility of using microorganisms for enhanced oil recovery (EOR). Research has shown that microbial EOR can increase production at lower costs than conventional oil recovery. The use of bacteria has also proven to be a feasible treatment method in the biodegradation of hydrocarbons associated with oil spills. refs., tabs., figs

[Characterization and microbial community shifts of rice strawdegrading microbial consortia].

Science.gov (United States)

Wang, Chunfang; Ma, Shichun; Huang, Yan; Liu, Laiyan; Fan, Hui; Deng, Yu

2016-12-04

To study the relationship between microbial community and degradation rate of rice straw, we compared and analyzed cellulose-decomposing ability, microbial community structures and shifts of microbial consortia F1 and F2. We determined exoglucanase activity by 3, 5-dinitrosalicylic acid colorimetry. We determined content of cellulose, hemicellulose and lignin in rice straw by Van Soest method, and calculated degradation rates of rice straw by the weight changes before and after a 10-day incubation. We analyzed and compared the microbial communities and functional microbiology shifts by clone libraries, Miseq analysis and real time-PCR based on the 16S rRNA gene and cel48 genes. Total degradation rate, cellulose, and hemicellulose degradation rate of microbial consortia F1 were significantly higher than that of F2. The variation trend of exoglucanase activity in both microbial consortia F1 and F2 was consistent with that of cel48 gene copies. Microbial diversity of F1 was complex with aerobic bacteria as dominant species, whereas that of F2 was simple with a high proportion of anaerobic cellulose decomposing bacteria in the later stage of incubation. In the first 4 days, unclassified Bacillales and Bacillus were dominant in both F1 and F2. The dominant species and abundance became different after 4-day incubation, Bacteroidetes and Firmicutes were dominant phyla of F1 and F2, respectively. Although Petrimonas and Pusillimonas were common dominant species in F1 and F2, abundance of Petrimonas in F2 (38.30%) was significantly higher than that in F1 (9.47%), and the abundance of Clostridiales OPB54 in F2 increased to 14.85% after 8-day incubation. The abundance of cel48 gene related with cellulose degradation rate and exoglucanase activity, and cel48 gene has the potential as a molecular marker to monitor the process of cellulose degradation. Microbial community structure has a remarkable impact on the degradation efficiency of straw cellulose, and Petrimonas

The significance of microbial processes in hydrogeology and geochemistry

Science.gov (United States)

Chapelle, Francis H.

Microbial processes affect the chemical composition of groundwater and the hydraulic properties of aquifers in both contaminated and pristine groundwater systems. The patterns of water-chemistry changes that occur depend upon the relative abundance of electron donors and electron acceptors. In many pristine aquifers, where microbial metabolism is limited by the availability of electron donors (usually organic matter), dissolved inorganic carbon (DIC) accumulates slowly along aquifer flow paths and available electron acceptors are consumed sequentially in the order dissolved oxygen >nitrate>Fe(III)>sulfate>CO2 (methanogenesis). In aquifers contaminated by anthropogenic contaminants, an excess of available organic carbon often exists, and microbial metabolism is limited by the availability of electron acceptors. In addition to changes in groundwater chemistry, the solid matrix of the aquifer is affected by microbial processes. The production of carbon dioxide and organic acids can lead to increased mineral solubility, which can lead to the development of secondary porosity and permeability. Conversely, microbial production of carbonate, ferrous iron, and sulfide can result in the precipitation of secondary calcite or pyrite cements that reduce primary porosity and permeability in groundwater systems. Les processus microbiologiques peuvent affecter la composition chimique de l'eau souterraine et les propriétés hydrauliques des nappes aussi bien dans les systèmes aquifères pollués que dans les systèmes indemnes de pollution. Les changements de chimisme des eaux qui se produisent dépendent de l'abondance relative des donneurs et des accepteurs d'électrons. Dans les aquifères non contaminés, où le métabolisme microbien est limité par la disponibilité des donneurs d'électrons (en général la matière organique), le carbone minéral dissous (CMD) s'accumule lentement le long des axes d'écoulement souterrain et les accepteurs d'électrons disponibles sont

Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

International Nuclear Information System (INIS)

Joel E. Kostka; Lainie Petrie; Nadia North; David L. Balkwill; Joseph W. Stucki; Lee Kerkhof

2004-01-01

The overall objective of our project is to understand the microbial and geochemical mechanisms controlling the reduction and immobilization of U(VI) during biostimulation in subsurface sediments of the Field Research Center (FRC) which are cocontaminated with uranium and nitrate. The focus will be on activity of microbial populations (metal- and nitrate-reducing bacteria) and iron minerals which are likely to make strong contributions to the fate of uranium during in situ bioremediation. The project will: (1) quantify the relationships between active members of the microbial communities, iron mineralogy, and nitrogen transformations in the field and in laboratory incubations under a variety of biostimulation conditions, (2) purify and physiologically characterize new model metal-reducing bacteria isolated from moderately acidophilic FRC subsurface sediments, and (3) elucidate the biotic and abiotic mechanisms by which FRC aluminosilicate clay minerals are reduced and dissolved under environmental conditions resembling those during biostimulation. Active microbial communities will be assessed using quantitative molecular techniques along with geochemical measurements to determine the different terminal-electron-accepting pathways. Iron minerals will be characterized using a suite of physical, spectroscopic, and wet chemical methods. Monitoring the activity and composition of the denitrifier community in parallel with denitrification intermediates during nitrate removal will provide a better understanding of the indirect effects of nitrate reduction on uranium speciation. Through quantification of the activity of specific microbial populations and an in-depth characterization of Fe minerals likely to catalyze U sorption/precipitation, we will provide important inputs for reaction-based biogeochemical models which will provide the basis for development of in situ U bioremediation strategies. In collaboration with Jack Istok and Lee Krumholz, we have begun to study the

Effect of power shape on energy extraction from microbial fuel cell

Science.gov (United States)

Alaraj, Muhannad; Feng, Shuo; Roane, Timberley M.; Park, Jae-Do

2017-10-01

Microbial fuel cells (MFCs) generate renewable energy in the form of direct current (DC) power. Harvesting energy from MFCs started with passive components such as resistors and capacitors, then charge pumps were introduced with some more advantages. Power electronics converters were later preferred due to their higher efficiency and controllability; however, they introduce high frequency current ripple due to their high frequency switching. In this paper, the effect of shape of power extraction on MFC performance was investigated using three types of current shapes: continuous, square-wave, and triangular-wave. Simultaneously, chemical parameters, such as pH, dissolved oxygen, electrical conductivity, and redox potential, in the anode chamber were monitored to see how these parameters change with the shape of the electrical power extraction. Results showed that the shape of the extracted current did not have a substantial effect on the MFC life span, output power, and energy extraction, nor on the chemical parameters. The outcome of this study provided insight for the electrical impact by power electronics converters on some microbial and chemical aspects of an MFC system.

Electricity generation by microbial fuel cells fuelled with wheat straw hydrolysate

DEFF Research Database (Denmark)

Thygesen, Anders; Poulsen, Finn Willy; Angelidaki, Irini

2011-01-01

Electricity production from microbial fuel cells fueled with hydrolysate produced by hydrothermal treatment of wheat straw can achieve both energy production and domestic wastewater purification. The hydrolysate contained mainly xylan, carboxylic acids, and phenolic compounds. Power generation...... in 95% degradation of the xylan and glucan. The study demonstrates that lignocellulosic hydrolysate can be used for co-treatment with domestic wastewater for power generation in microbial fuel cells....... density with the hydrolysate was higher than the one with only xylan (120 mW m−2) and carboxylic acids as fuel. The higher power density can be caused by the presence of phenolic compounds in the hydrolysates, which could mediate electron transport. Electricity generation with the hydrolysate resulted...

Electron transfer pathways in microbial oxygen biocathodes

Energy Technology Data Exchange (ETDEWEB)

Freguia, Stefano, E-mail: stefano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Tsujimura, Seiya, E-mail: seiya@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan); Kano, Kenji, E-mail: kkano@kais.kyoto-u.ac.j [Bio-analytical and Physical Chemistry Laboratory, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8205 (Japan)

2010-01-01

The ability of some bacteria to enhance the rate of cathodic oxygen reduction to water has been recently discovered, opening the way to an entirely renewable and environmentally friendly concept of biocathode. In this study we reveal that several mechanisms may induce catalytic effects by bacteria. These comprise mechanisms that are putatively beneficial to the bacteria as well as mechanisms which are merely side effects, including quinone autoxidation and direct O{sub 2} reduction by heme compounds. Here we showed that 1 muM of ACNQ is able to generate a significant catalytic wave for oxygen reduction, with onset at approximately 0 V vs. SHE. Similarly, adsorption of hemin on a carbon surface catalyses O{sub 2} reduction to H{sub 2}O{sub 2} with an onset of +0.2 V vs. SHE. To evaluate the catalytic pathways of live cells on cathodic oxygen reduction, two species of electrochemically active bacteria were selected as pure cultures, namely Acinetobacter calcoaceticus and Shewanella putrefaciens. The former appears to exploit a self-excreted redox compound with redox characteristics matching those of pyrroloquinoline quinone (PQQ) for extracellular electron transfer. The latter appears to utilise outer membrane-bound redox compounds. Interaction of quinones and cytochromes with the membrane-bound electron transfer chain is yet to be proven.

Tissue transglutaminase (TG2 activity regulates osteoblast differentiation and mineralization in the SAOS-2 cell line

Directory of Open Access Journals (Sweden)

Xiaoxue Yin

2012-08-01

Full Text Available Tissue transglutaminase (type II, TG2 has long been postulated to directly promote skeletal matrix calcification and play an important role in ossification. However, limited information is available on the expression, function and modulating mechanism of TG2 during osteoblast differentiation and mineralization. To address these issues, we cultured the well-established human osteosarcoma cell line SAOS-2 with osteo-inductive conditioned medium and set up three time points (culture days 4, 7, and 14 to represent different stages of SAOS-2 differentiation. Osteoblast markers, mineralization, as well as TG2 expression and activity, were then assayed in each stage. Furthermore, we inhibited TG activity with cystamine and then checked SAOS-2 differentiation and mineralization in each stage. The results showed that during the progression of osteoblast differentiation SAOS-2 cells presented significantly high levels of osteocalcin (OC mRNA, bone morphogenetic protein-2 (BMP-2 and collagen I, significantly high alkaline phosphatase (ALP activity, and the increased formation of calcified matrix. With the same tendency, TG2 expression and activity were up-regulated. Furthermore, inhibition of TG activity resulted in a significant decrease of OC, collagen I, and BMP-2 mRNA and of ALP activity and mineralization. This study demonstrated that TG2 is involved in osteoblast differentiation and may play a role in the initiation and regulation of the mineralization processes. Moreover, the modulating effects of TG2 on osteoblasts may be related to BMP-2.

Effect of multiwalled carbon nanotubes on UASB microbial consortium.

Science.gov (United States)

Yadav, Tushar; Mungray, Alka A; Mungray, Arvind K

2016-03-01

The continuous rise in production and applications of carbon nanotubes (CNTs) has grown a concern about their fate and toxicity in the environment. After use, these nanomaterials pass through sewage and accumulate in wastewater treatment plants. Since, such plants rely on biological degradation of wastes; their activity may decrease due to the presence of CNTs. This study investigated the effect of multiwalled carbon nanotubes (MWCNTs) on upflow anaerobic sludge blanket (UASB) microbial activity. The toxic effect on microbial viability, extracellular polymeric substances (EPS), volatile fatty acids (VFA), and biogas generation was determined. The reduction in a colony-forming unit (CFU) was 29 and 58 % in 1 and 100 mg/L test samples, respectively, as compared to control. The volatile fatty acids and biogas production was also found reduced. The scanning electron microscopy (SEM) and fluorescent microscopy images confirmed that the MWCNT mediated microbial cell damage. This damage caused the increase in EPS carbohydrate, protein, and DNA concentration. Fourier transform infrared (FTIR) spectroscopy results supported the alterations in sludge EPS due to MWCNT. Our observations offer a new insight to understand the nanotoxic effect of MWCNTs on UASB microflora in a complex environment system.

Power output of microbial fuel cell emphasizing interaction of anodic binder with bacteria

Science.gov (United States)

Li, Hongying; Liao, Bo; Xiong, Juan; Zhou, Xingwang; Zhi, Huozhen; Liu, Xiang; Li, Xiaoping; Li, Weishan

2018-03-01

Electrochemically active biofilm is necessary for the electron transfer between bacteria and anodic electrode in microbial fuel cells and selecting the type of anodic electrode material that favours formation of electrochemically active biofilm is crucial for the microbial fuel cell operation. We report a new finding that the interaction of anodic binder with bacteria plays more important role than its hydrophilicity for forming an electrochemically active biofilm, which is emphasized by applying poly(bisphenol A-co-epichorohydrin) as an anodic binder of the microbial fuel cell based on carbon nanotubes as anodic electrode and Escherichia coli as bacterium. The physical characterizations and electrochemical measurements demonstrate that poly(bisphenol A-co-epichorohydrin) exhibits a strong interaction with bacteria and thus provides the microbial fuel cell with excellent power density output. The MFC using poly(bisphenol A-co-epichorohydrin) reaches a maximum power density output of 3.8 W m-2. This value is larger than that of the MFCs using polytetrafluoroethylene that has poorer hydrophilicity, or polyvinyl alcohol that has better hydrophilicity but exhibits weaker interaction with bacteria than poly(bisphenol A-co-epichorohydrin).

Green coffee decontamination by electron beam irradiation

International Nuclear Information System (INIS)

Nemtanu, Monica R.; Brasoveanu, Mirela; Grecu, Maria Nicoleta; Minea, R.

2005-01-01

Microbiological load of green coffee is a real problem considering that it is extremely sensitive to contamination. Irradiation is a decontamination method for a lot of foodstuffs, being a feasible, very effective and environment friendly one. Beans and ground green coffee were irradiated with electron beams up to 40 kGy. Microbial load, rheological behavior, electron paramagnetic resonance (EPR) and visible spectroscopy were carried out. The results show that electron beam irradiation of green coffee could decontaminate it without severe changes in its properties

Microbial Gas Generation Under Expected Waste Isolation Pilot Plant Repository Conditions: Final Report

International Nuclear Information System (INIS)

Gillow, J.B.; Francis, A.

2011-01-01

Gas generation from the microbial degradation of the organic constituents of transuranic (TRU) waste under conditions expected in the Waste Isolation Pilot Plant (WIPP) was investigated. The biodegradation of mixed cellulosic materials and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, hypalon, leaded hypalon, and neoprene) was examined. We evaluated the effects of environmental variables such as initial atmosphere (air or nitrogen), water content (humid (∼70% relative humidity, RH) and brine inundated), and nutrient amendments (nitogen phosphate, yeast extract, and excess nitrate) on microbial gas generation. Total gas production was determined by pressure measurement and carbon dioxide (CO 2 ) and methane (CH 4 ) were analyzed by gas chromatography; cellulose degradation products in solution were analyzed by high-performance liquid chromatography. Microbial populations in the samples were determined by direct microscopy and molecular analysis. The results of this work are summarized.

Microbial conversion technologies

Energy Technology Data Exchange (ETDEWEB)

Lau, P. [National Research Council of Canada, Ottawa, ON (Canada). Bioconversion and Sustainable Development

2006-07-01

Microbes are a biomass and an valuable resource. This presentation discussed microbial conversion technologies along with background information on microbial cells, their characteristics and microbial diversity. Untapped opportunities for microbial conversion were identified. Metagenomic and genome mining approaches were also discussed, as they can provide access to uncultivated or unculturable microorganisms in communal populations and are an unlimited resource for biocatalysts, novel genes and metabolites. Genome mining was seen as an economical approach. The presentation also emphasized that the development of microbial biorefineries would require significant insights into the relevant microorganisms and that biocatalysts were the ultimate in sustainability. In addition, the presentation discussed the natural fibres initiative for biochemicals and biomaterials. Anticipated outputs were identified and work in progress of a new enzyme-retting cocktail to provide diversity and/or consistency in fibre characteristics for various applications were also presented. It was concluded that it is necessary to leverage understanding of biological processes to produce bioproducts in a clean and sustainable manner. tabs., figs.

Microbial colonization of biopolymeric thin films containing natural compounds and antibiotics fabricated by MAPLE

Energy Technology Data Exchange (ETDEWEB)

Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele (Romania); Surdu, A.V.; Grumezescu, A.M.; Oprea, A.E.; Trusca, R.; Vasile, O. [Faculty of Applied Chemistry and Materials Science, Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, Polizu Street No. 1–7, 011061 Bucharest (Romania); Dorcioman, G.; Visan, A.; Socol, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, PO Box MG-36, Bucharest-Magurele (Romania); Mihaiescu, D. [Faculty of Applied Chemistry and Materials Science, Department of Organic Chemistry, Politehnica University of Bucharest, 1–7 Polizu Street, 011061 Bucharest (Romania); Enculescu, M. [National Institute of Materials Physics, PO Box MG-7, Bucharest-Magurele (Romania); Chifiriuc, M.C. [Microbiology Immunology Department, Faculty of Biology, Research Institute of the University of Bucharest—ICUB, Research Institute of the University of Bucharest, 77206 Bucharest (Romania); Boehm, R.D.; Narayan, R.J. [Biomedical Engineering, University of North Carolina, Chapel Hill, NC (United States); Chrisey, D.B. [Department of Physics and Engineering Physics, Tulane University, New Orleans, LA (United States)

2015-05-01

Highlights: • We deposited thin composite quercetin/polyvinylpyrrolidone/antibiotic films with close resemblance to the starting/drop-cast composition by MAPLE. • Quercetin flavonoid shows an anti-biofilm activity comparable to that of the tested large-spectrum antibiotics (norfloxacin or cefuroxime), especially in case of 72 h biofilms. • These results could account for the possible use of quercetin as an alternative to antibiotics to combat the mature biofilms developed on different substrates. • MAPLE may be used to produce implantable medical devices that provide a relatively long term in vitro stability and resistance to the growth of microorganisms. - Abstract: Although a great number of antibiotics are currently available, they are often rendered ineffective by the ability of microbial strains to develop genetic resistance and to grow in biofilms. Since many antimicrobial agents poorly penetrate biofilms, biofilm-associated infections often require high concentrations of antimicrobial agents for effective treatment. Among the various strategies that may be used to inhibit microbial biofilms, one strategy that has generated significant interest involves the use of bioactive surfaces that are resistant to microbial colonization. In this respect, we used matrix assisted pulsed laser evaporation (MAPLE) involving a pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) to obtain thin composite biopolymeric films containing natural (flavonoid) or synthetic (antibiotic) compounds as bioactive substances. Chemical composition and film structures were investigated by Fourier transform infrared spectroscopy and X-ray diffraction. Films morphology was studied by scanning electron microscopy and transmission electron microscopy. The antimicrobial assay of the microbial biofilms formed on these films was assessed by the viable cell counts method. The flavonoid-containing thin films showed increased resistance to microbial colonization

Microbial colonization of biopolymeric thin films containing natural compounds and antibiotics fabricated by MAPLE

International Nuclear Information System (INIS)

Cristescu, R.; Surdu, A.V.; Grumezescu, A.M.; Oprea, A.E.; Trusca, R.; Vasile, O.; Dorcioman, G.; Visan, A.; Socol, G.; Mihailescu, I.N.; Mihaiescu, D.; Enculescu, M.; Chifiriuc, M.C.; Boehm, R.D.; Narayan, R.J.; Chrisey, D.B.

2015-01-01

Highlights: • We deposited thin composite quercetin/polyvinylpyrrolidone/antibiotic films with close resemblance to the starting/drop-cast composition by MAPLE. • Quercetin flavonoid shows an anti-biofilm activity comparable to that of the tested large-spectrum antibiotics (norfloxacin or cefuroxime), especially in case of 72 h biofilms. • These results could account for the possible use of quercetin as an alternative to antibiotics to combat the mature biofilms developed on different substrates. • MAPLE may be used to produce implantable medical devices that provide a relatively long term in vitro stability and resistance to the growth of microorganisms. - Abstract: Although a great number of antibiotics are currently available, they are often rendered ineffective by the ability of microbial strains to develop genetic resistance and to grow in biofilms. Since many antimicrobial agents poorly penetrate biofilms, biofilm-associated infections often require high concentrations of antimicrobial agents for effective treatment. Among the various strategies that may be used to inhibit microbial biofilms, one strategy that has generated significant interest involves the use of bioactive surfaces that are resistant to microbial colonization. In this respect, we used matrix assisted pulsed laser evaporation (MAPLE) involving a pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) to obtain thin composite biopolymeric films containing natural (flavonoid) or synthetic (antibiotic) compounds as bioactive substances. Chemical composition and film structures were investigated by Fourier transform infrared spectroscopy and X-ray diffraction. Films morphology was studied by scanning electron microscopy and transmission electron microscopy. The antimicrobial assay of the microbial biofilms formed on these films was assessed by the viable cell counts method. The flavonoid-containing thin films showed increased resistance to microbial colonization

Pyrosequencing analysis yields comprehensive assessment of microbial communities in pilot-scale two-stage membrane biofilm reactors.

Science.gov (United States)

Ontiveros-Valencia, Aura; Tang, Youneng; Zhao, He-Ping; Friese, David; Overstreet, Ryan; Smith, Jennifer; Evans, Patrick; Rittmann, Bruce E; Krajmalnik-Brown, Rosa

2014-07-01

We studied the microbial community structure of pilot two-stage membrane biofilm reactors (MBfRs) designed to reduce nitrate (NO3(-)) and perchlorate (ClO4(-)) in contaminated groundwater. The groundwater also contained oxygen (O2) and sulfate (SO4(2-)), which became important electron sinks that affected the NO3(-) and ClO4(-) removal rates. Using pyrosequencing, we elucidated how important phylotypes of each "primary" microbial group, i.e., denitrifying bacteria (DB), perchlorate-reducing bacteria (PRB), and sulfate-reducing bacteria (SRB), responded to changes in electron-acceptor loading. UniFrac, principal coordinate analysis (PCoA), and diversity analyses documented that the microbial community of biofilms sampled when the MBfRs had a high acceptor loading were phylogenetically distant from and less diverse than the microbial community of biofilm samples with lower acceptor loadings. Diminished acceptor loading led to SO4(2-) reduction in the lag MBfR, which allowed Desulfovibrionales (an SRB) and Thiothrichales (sulfur-oxidizers) to thrive through S cycling. As a result of this cooperative relationship, they competed effectively with DB/PRB phylotypes such as Xanthomonadales and Rhodobacterales. Thus, pyrosequencing illustrated that while DB, PRB, and SRB responded predictably to changes in acceptor loading, a decrease in total acceptor loading led to important shifts within the "primary" groups, the onset of other members (e.g., Thiothrichales), and overall greater diversity.

Anode modification with formic acid: A simple and effective method to improve the power generation of microbial fuel cells

Energy Technology Data Exchange (ETDEWEB)

Liu, Weifeng; Cheng, Shaoan, E-mail: shaoancheng@zju.edu.cn; Guo, Jian

2014-11-30

Highlights: • Carbon cloth anode is modified with formic acid by a simple and reliable approach. • The modification significantly enhances the power output of microbial fuel cells. • The modified anode surface favors the bacterial attachment and growth on anode. • The electron transfer rate of anode is promoted. - Abstract: The physicochemical properties of anode material directly affect the anodic biofilm formation and electron transfer, thus are critical for the power generation of microbial fuel cells (MFCs). In this work, carbon cloth anode was modified with formic acid to enhance the power production of MFCs. Formic acid modification of anode increased the maximum power density of a single-chamber air-cathode MFC by 38.1% (from 611.5 ± 6 mW/m{sup 2} to 877.9 ± 5 mW/m{sup 2}). The modification generated a cleaner electrode surface and a reduced content of oxygen and nitrogen groups on the anode. The surface changes facilitated bacterial growth on the anode and resulted in an optimized microbial community. Thus, the electron transfer rate on the modified anodes was enhanced remarkably, contributing to a higher power output of MFCs. Anode modification with formic acid could be an effective and simple method for improving the power generation of MFCs. The modification method holds a huge potential for large scale applications and is valuable for the scale-up and commercialization of microbial fuel cells.

Effect of pre-acclimation of granular activated carbon on microbial electrolysis cell startup and performance

KAUST Repository

LaBarge, Nicole; Yilmazel, Yasemin Dilsad; Hong, Pei-Ying; Logan, Bruce E.

2016-01-01

) was used to pre-enrich electrotrophic methanogenic communities, as GAC has been shown to stimulate direct transfer of electrons between different microbial species. MEC startup times using pre-acclimated GAC were improved compared to controls (without pre

Something new from something old? Fracking stimulated microbial processes

Science.gov (United States)

Wrighton, K. C.; Daly, R. A.; Hoyt, D.; Trexler, R.; McRae, J.; Wilkins, M.; Mouser, P. J.

2015-12-01

Hydraulic fracturing, colloquially known as "fracking", is employed for effective gas and oil recovery in deep shales. This process injects organisms and liquids from the surface into the deep subsurface (~2500 m), exposing microorganisms to high pressures, elevated temperatures, chemical additives, and brine-level salinities. Here we use assembly-based metagenomics to create a metabolic blueprint from an energy-producing Marcellus shale well over a 328-day period. Using this approach we ask the question: What abiotic and biotic factors drive microbial metabolism and thus biogeochemical cycling during natural gas extraction? We found that after 49 days, increased salinity in produced waters corresponded to a shift in the microbial community, with only organisms that encode salinity adaptations detected. We posit that organic compatible solutes, produced by organisms adapting to increased salinity, fuels a methylamine-driven ecosystem in fractured shale. This metabolic network ultimately results in biogenic methane production from members of Methanohalophilus and Methanolobus. Proton NMR validated these genomic hypotheses, with mono-methylamine being highest in the input material, but detected throughout the sampling. Beyond abiotic constraints, our genomic investigations revealed that viruses can be linked to key members of the microbial community, potentially releasing methylamine osmoprotectants and impacting bacterial strain variation. Collectively our results indicate that adaptation to high salinity, metabolism in the absence of oxidized electron acceptors, and viral predation are controlling factors mediating microbial community metabolism during hydraulic fracturing of the deep subsurface.

Detrital microbial community development and phosphorus dynamics in a stream ecosystem

International Nuclear Information System (INIS)

Perkins, R.E.; Elwood, J.W.; Sayler, G.S.

1986-06-01

Detrital microbial community development and phosphorus dynamics in a lotic system were investigated in non-recirculating laboratory streams contains leaf detritus. Temporal patterns of microbial colonization, as determined by scanning electron microscopy, indicate leaf species dependency and that bacteria were the first colonizers followed by fungi. An extensive glycocalyx layer developed. Phosphorus incorporation rates of both the whole community and intracellular components were determined by time-course measurements of 33 PO 4 or 32 PO 4 . Phosphorus turnover rates were determined by a sequential double-labeling procedure using 33 PO 4 and 32 PO 4 , in which the microbiota were labeled with 33 P until in isotopic equilibrium, then 32 P was added. The turnover rate was determined by time-course measurements of the ratio 32 P to 33 P. Snail grazing resulted in an increase in phosphorus metabolism per unit microbial biomass; however, per unit area of leaf surface no increase was observed. Grazing also caused a two-fold reduction in microbial biomass. The results indicate that microbiota associated with decomposing leaves slowly recycle phosphorus, are slowly growing, and have a low metabolic activity. The spiraling length is shortened by microbiota on a short-term basis; however, it may increase on a long-term basis due to hydrological transport of detritus downstream

Microbial Inoculants and Their Impact on Soil Microbial Communities: A Review

Directory of Open Access Journals (Sweden)

Darine Trabelsi

2013-01-01

Full Text Available 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.

Potential for direct interspecies electron transfer in methanogenic wastewater digester aggregates

DEFF Research Database (Denmark)

Morita, Masahiko; Malvankar, Nikhil S; Franks, Ashley E

2011-01-01

Mechanisms for electron transfer within microbial aggregates derived from an upflow anaerobic sludge blanket reactor converting brewery waste to methane were investigated in order to better understand the function of methanogenic consortia. The aggregates were electrically conductive, with conduc...... for electron exchange in some methanogenic systems....

Molecular microbial ecology manual

NARCIS (Netherlands)

Kowalchuk, G.A.; Bruijn, de F.J.; Head, I.M.; Akkermans, A.D.L.

2004-01-01

The field of microbial ecology has been revolutionized in the past two decades by the introduction of molecular methods into the toolbox of the microbial ecologist. This molecular arsenal has helped to unveil the enormity of microbial diversity across the breadth of the earth's ecosystems, and has

Meta-Transcriptomic Analysis of a Chromate-Reducing Aquifer Microbial Community

Science.gov (United States)

Beller, H. R.; Brodie, E. L.; Han, R.; Karaoz, U.

2010-12-01

A major challenge for microbial ecology that has become more tractable in the advent of new molecular techniques is characterizing gene expression in complex microbial communities. We are using meta-transcriptomic analysis to characterize functional changes in an aquifer-derived, chromate-reducing microbial community as it transitions through various electron-accepting conditions. We inoculated anaerobic microcosms with groundwater from the Cr-contaminated Hanford 100H site and supplemented them with lactate and electron acceptors present at the site, namely, nitrate, sulfate, and Fe(III). The microcosms progressed successively through various electron-accepting conditions (e.g., denitrifying, sulfate-reducing, and ferric iron-reducing conditions, as well as nitrate-dependent, chemolithotrophic Fe(II)-oxidizing conditions). Cr(VI) was rapidly reduced initially and again upon further Cr(VI) amendments. Extensive geochemical sampling and analysis (e.g., lactate, acetate, chloride, nitrate, nitrite, sulfate, dissolved Cr(VI), total Fe(II)), RNA/DNA harvesting, and PhyloChip analyses were conducted. Methods were developed for removal of rRNA from total RNA in preparation for meta-transcriptome sequencing. To date, samples representing denitrifying and fermentative/sulfate-reducing conditions have been sequenced using 454 Titanium technology. Of the non-rRNA related reads for the denitrifying sample (which was also actively reducing chromate), ca. 8% were associated with denitrification and ca. 0.9% were associated with chromate resistance/transport, in contrast to the fermentative/sulfate-reducing sample (in which chromate had already been reduced), which had zero reads associated with either of these categories but many predicted proteins associated with sulfate-reducing bacteria. We observed sequences for key functional transcripts that were unique at the nucleotide level compared to the GenBank non-redundant database [such as L-lactate dehydrogenase (iron

Are underground clay disposal conditions favorable for microbial activity and bio-corrosion?

Energy Technology Data Exchange (ETDEWEB)

Libert, M.; Kerber-Schuetz, M.; Bildstein, O. [CEA, DEN/DTN/SMTM/LMTE, bat. 307, 13108 Saint Paul Lez Durance Cedex (France); Esnault, L. [ECOGEOSAFE, Technopole de l' Environnement Arbois- Mediterranee, BP 90027 Aix en Provence (France)

2013-07-01

The French concept for geological disposal of high-level radioactive waste is based on a multi-barrier system including metallic containers confined in a clay-stone layer. The main alteration vector is water coming from the host rock and triggering corrosion of metallic components. Despite extreme conditions, microorganisms can adapt and survive in these environments. Anoxic corrosion of metallic containers and water radiolysis produce H{sub 2}, which potentially represents an abundant energetic source for microbial development, especially in this type of environment containing low amounts of biodegradable organic matter. Moreover, formation of Fe(III)-bearing corrosion products such as magnetite (Fe{sub 3}O{sub 4}) can provide electron acceptors for microbial development. Therefore, bio-corrosion studies are needed in order to investigate the activity of hydrogenotrophic bacteria able to reduce sulphates or Fe(III) from iron oxides (passive layer). These studies help in evaluating such microbial impacts on the long-term stability of metallic components involved in radioactive waste disposal. (authors)

Relating Anaerobic Digestion Microbial Community and Process Function : Supplementary Issue: Water Microbiology

Directory of Open Access Journals (Sweden)

Kaushik Venkiteshwaran

2015-01-01

Full Text Available Anaerobic digestion (AD involves a consortium of microorganisms that convert substrates into biogas containing methane for renewable energy. The technology has suffered from the perception of being periodically unstable due to limited understanding of the relationship between microbial community structure and function. The emphasis of this review is to describe microbial communities in digesters and quantitative and qualitative relationships between community structure and digester function. Progress has been made in the past few decades to identify key microorganisms influencing AD. Yet, more work is required to realize robust, quantitative relationships between microbial community structure and functions such as methane production rate and resilience after perturbations. Other promising areas of research for improved AD may include methods to increase/control (1 hydrolysis rate, (2 direct interspecies electron transfer to methanogens, (3 community structure–function relationships of methanogens, (4 methanogenesis via acetate oxidation, and (5 bioaugmentation to study community–activity relationships or improve engineered bioprocesses.

Microbial electrosynthetic cells

Energy Technology Data Exchange (ETDEWEB)

May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

2018-01-30

Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

Microbial transformations of radionuclides released from nuclear fuel reprocessing plants

International Nuclear Information System (INIS)

Francis, A.J.

2007-01-01

Microorganisms can affect the stability and mobility of the actinides U, Pu, Cm, Am, Np, and the fission products Tc, I, Cs, Sr, released from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been investigated, we have only limited information on the effects of microbial processes. The mechanisms of microbial transformations of the major and minor actinides and the fission products under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed. (author)

Exploring Biogeochemistry and Microbial Diversity of Extant Microbialites in Mexico and Cuba

Science.gov (United States)

Valdespino-Castillo, Patricia M.; Hu, Ping; Merino-Ibarra, Martín; López-Gómez, Luz M.; Cerqueda-García, Daniel; González-De Zayas, Roberto; Pi-Puig, Teresa; Lestayo, Julio A.; Holman, Hoi-Ying; Falcón, Luisa I.

2018-01-01

Microbialites are modern analogs of ancient microbial consortia that date as far back as the Archaean Eon. Microbialites have contributed to the geochemical history of our planet through their diverse metabolic capacities that mediate mineral precipitation. These mineral-forming microbial assemblages accumulate major ions, trace elements and biomass from their ambient aquatic environments; their role in the resulting chemical structure of these lithifications needs clarification. We studied the biogeochemistry and microbial structure of microbialites collected from diverse locations in Mexico and in a previously undescribed microbialite in Cuba. We examined their structure, chemistry and mineralogy at different scales using an array of nested methods including 16S rRNA gene high-throughput sequencing, elemental analysis, X-Ray fluorescence (XRF), X-Ray diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), Fourier Transformed Infrared (FTIR) spectroscopy and Synchrotron Radiation-based Fourier Transformed Infrared (SR-FTIR) spectromicroscopy. The resulting data revealed high biological and chemical diversity among microbialites and specific microbe to chemical correlations. Regardless of the sampling site, Proteobacteria had the most significant correlations with biogeochemical parameters such as organic carbon (Corg), nitrogen and Corg:Ca ratio. Biogeochemically relevant bacterial groups (dominant phototrophs and heterotrophs) showed significant correlations with major ion composition, mineral type and transition element content, such as cadmium, cobalt, chromium, copper and nickel. Microbial-chemical relationships were discussed in reference to microbialite formation, microbial metabolic capacities and the role of transition elements as enzyme cofactors. This paper provides an analytical baseline to drive our understanding of the links between microbial diversity with the chemistry of their lithified precipitations. PMID

Microbial bioinformatics 2020.

Science.gov (United States)

Pallen, Mark J

2016-09-01

Microbial bioinformatics in 2020 will remain a vibrant, creative discipline, adding value to the ever-growing flood of new sequence data, while embracing novel technologies and fresh approaches. Databases and search strategies will struggle to cope and manual curation will not be sustainable during the scale-up to the million-microbial-genome era. Microbial taxonomy will have to adapt to a situation in which most microorganisms are discovered and characterised through the analysis of sequences. Genome sequencing will become a routine approach in clinical and research laboratories, with fresh demands for interpretable user-friendly outputs. The "internet of things" will penetrate healthcare systems, so that even a piece of hospital plumbing might have its own IP address that can be integrated with pathogen genome sequences. Microbiome mania will continue, but the tide will turn from molecular barcoding towards metagenomics. Crowd-sourced analyses will collide with cloud computing, but eternal vigilance will be the price of preventing the misinterpretation and overselling of microbial sequence data. Output from hand-held sequencers will be analysed on mobile devices. Open-source training materials will address the need for the development of a skilled labour force. As we boldly go into the third decade of the twenty-first century, microbial sequence space will remain the final frontier! © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Ecology and life history of an amoebomastigote, Paratetramitus jugosus, from a microbial mat: new evidence for multiple fission

Science.gov (United States)

Enzien, M.; McKhann, H. I.; Margulis, L.

1989-01-01

Five microbial habitats (gypsum crust, gypsum photosynthetic community, Microcoleus mat, Thiocapsa scum, and black mud) were sampled for the presence of the euryhaline, rapidly growing amoebomastigote, Paratetramitus jugosus. Field investigations of microbial mats from Baja California Norte, Mexico, and Salina Bido near Matanzas, Cuba, reveal that P. jugosus is most frequently found in the Thiocapsa layer of microbial mats. Various stages of the life history were studied using phase-contrast, differential-interference, and transmission electron microscopy. Mastigote stages were induced and studied by electron microscopy; mastigotes that actively feed on bacteria bear two or more undulipodia. A three-dimensional drawing of the kinetid ("basal apparatus") based on electron micrographs is presented. Although promitoses were occasionally observed, it is unlikely that they can account for the rapid growth of P. jugosus populations on culture media. Dense, refractile, spherical, and irregular-shaped bodies were seen at all times in all cultures along with small mononucleate (approximately 2-7 micrometers diameter) amoebae. Cytochemical studies employing two different fluorescent stains for DNA (DAPI, mithramycin) verified the presence of DNA in these small bodies. Chromatin-like material seen in electron micrographs within the cytoplasm and blebbing off nuclei were interpreted to the chromatin bodies. Our interpretation, consistent with the data but not proven, is that propagation by multiple fission of released chromatin bodies that become small amoebae may occur in Paratetramitus jugosus. These observations are consistent with descriptions of amoeba propagules in the early literature (Hogue, 1914).

Exploring optimal supplement strategy of medicinal herbs and tea extracts for bioelectricity generation in microbial fuel cells.

Science.gov (United States)

Chen, Bor-Yann; Liao, Jia-Hui; Hsu, An-Wei; Tsai, Po-Wei; Hsueh, Chung-Chuan

2018-05-01

This first-attempt study used extracts of appropriate antioxidant abundant Camellia and non-Camellia tea and medicinal herbs as model ESs to stably intensify bioelectricity generation performance in microbial fuel cells (MFCs). As electron shuttles (ESs) could stimulate electron transport phenomena by significant reduction of electron transfer resistance, the efficiency of power generation for energy extraction in microbial fuel cells (MFCs) could be appreciably augmented. Using environmentally friendly natural bioresource as green bioresource of ESs is the most promising to sustainable practicability. As comparison of power-density profiles indicated, supplement of Camellia tea extracts would be the most appropriate, then followed non-Camellia Chrysanthemum tea and medicinal herbs. Antioxidant activities, total phenolic contents and power stimulating activities were all electrochemically associated. In particular, the extract of unfermented Camellia tea (i.e., green tea) was the most promising ESs to augment bioenergy extraction compared to other refreshing medicinal herb extracts. Copyright © 2018 Elsevier Ltd. All rights reserved.

Microbial Gas Generation Under Expected Waste Isolation Pilot Plant Repository Conditions: Final Report

Energy Technology Data Exchange (ETDEWEB)

Gillow, J.B.; Francis, A.

2011-07-01

Gas generation from the microbial degradation of the organic constituents of transuranic (TRU) waste under conditions expected in the Waste Isolation Pilot Plant (WIPP) was investigated. The biodegradation of mixed cellulosic materials and electron-beam irradiated plastic and rubber materials (polyethylene, polyvinylchloride, hypalon, leaded hypalon, and neoprene) was examined. We evaluated the effects of environmental variables such as initial atmosphere (air or nitrogen), water content (humid ({approx}70% relative humidity, RH) and brine inundated), and nutrient amendments (nitogen phosphate, yeast extract, and excess nitrate) on microbial gas generation. Total gas production was determined by pressure measurement and carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) were analyzed by gas chromatography; cellulose degradation products in solution were analyzed by high-performance liquid chromatography. Microbial populations in the samples were determined by direct microscopy and molecular analysis. The results of this work are summarized.

Isotopic insights into microbial sulfur cycling in oil reservoirs

Directory of Open Access Journals (Sweden)

Christopher G Hubbard

2014-09-01

Full Text Available Microbial sulfate reduction in oil reservoirs (biosouring is often associated with secondary oil production where seawater containing high sulfate concentrations (~28 mM is injected into a reservoir to maintain pressure and displace oil. The sulfide generated from biosouring can cause corrosion of infrastructure, health exposure risks, and higher production costs. Isotope monitoring is a promising approach for understanding microbial sulfur cycling in reservoirs, enabling early detection of biosouring, and understanding the impact of souring. Microbial sulfate reduction is known to result in large shifts in the sulfur and oxygen isotope compositions of the residual sulfate, which can be distinguished from other processes that may be occurring in oil reservoirs, such as precipitation of sulfate and sulfide minerals. Key to the success of this method is using the appropriate isotopic fractionation factors for the conditions and processes being monitored. For a set of batch incubation experiments using a mixed microbial culture with crude oil as the electron donor, we measured a sulfur fractionation factor for sulfate reduction of -30‰. We have incorporated this result into a simplified 1D reservoir reactive transport model to highlight how isotopes can help discriminate between biotic and abiotic processes affecting sulfate and sulfide concentrations. Modeling results suggest that monitoring sulfate isotopes can provide an early indication of souring for reservoirs with reactive iron minerals that can remove the produced sulfide, especially when sulfate reduction occurs in the mixing zone between formation waters containing elevated concentrations of volatile fatty acids and injection water containing elevated sulfate. In addition, we examine the role of reservoir thermal, geochemical, hydrological, operational and microbiological conditions in determining microbial souring dynamics and hence the anticipated isotopic signatures.

Evaluation of Laminaria-based microbial fuel cells (LbMs) for electricity production.

Science.gov (United States)

Gadhamshetty, Venkataramana; Belanger, Derek; Gardiner, Carly-Jeanne; Cummings, Anasha; Hynes, Anne

2013-01-01

Marine algae represents a sustainable feedstock in microbial fuel cells (MFCs) due to its low water and energy requirements for cultivation, higher capacity to sequester carbondioxide, and high carbohydrate content. Two-compartment MFCs were evaluated under batch-fed mode using Laminaria saccharina as the model for algae-based electron donor, and mixed microbial consortia as the biocatalyst, in the anode compartment. The Laminaria-based MFCs (LBMs) were studied with three different pretreatment conditions for the L. saccharina: (i) autoclaving (Auto), (ii) microwave irradiation (Micro), and (iii) as received treatment (No-Treat). A control was setup to establish base line performance for two-compartment MFCs using glucose as the electron donor in the anode. The performance of LBMs (250 mW/m(2) and 900 mA/m(2)) was on par with glucose-based MFCs. AC impedance analysis revealed that the charge transfer resistance was at least 50-fold higher than the corresponding ohmic losses in both LBMs and glucose-based MFCs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Conversion of Wastes into Bioelectricity and Chemicals by Using Microbial Electrochemical Technologies

KAUST Repository

Logan, B. E.

2012-08-09

Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a diverse platform of future sustainable energy and chemical production technologies. We review the key advances that will enable the use of exoelectrogenic microorganisms to generate biofuels, hydrogen gas, methane, and other valuable inorganic and organic chemicals. Moreover, we examine the key challenges for implementing these systems and compare them to similar renewable energy technologies. Although commercial development is already underway in several different applications, ranging from wastewater treatment to industrial chemical production, further research is needed regarding efficiency, scalability, system lifetimes, and reliability.

Conversion of wastes into bioelectricity and chemicals by using microbial electrochemical technologies.

Science.gov (United States)

Logan, Bruce E; Rabaey, Korneel

2012-08-10

Waste biomass is a cheap and relatively abundant source of electrons for microbes capable of producing electrical current outside the cell. Rapidly developing microbial electrochemical technologies, such as microbial fuel cells, are part of a diverse platform of future sustainable energy and chemical production technologies. We review the key advances that will enable the use of exoelectrogenic microorganisms to generate biofuels, hydrogen gas, methane, and other valuable inorganic and organic chemicals. Moreover, we examine the key challenges for implementing these systems and compare them to similar renewable energy technologies. Although commercial development is already underway in several different applications, ranging from wastewater treatment to industrial chemical production, further research is needed regarding efficiency, scalability, system lifetimes, and reliability.

Comparison of Two Mechanistic Microbial Growth Models to Estimate Shelf Life of Perishable Food Package under Dynamic Temperature Conditions

Directory of Open Access Journals (Sweden)

Dong Sun Lee

2014-01-01

Full Text Available Two mechanistic microbial growth models (Huang’s model and model of Baranyi and Roberts given in differential and integrated equation forms were compared in predicting the microbial growth and shelf life under dynamic temperature storage and distribution conditions. Literatures consistently reporting the microbial growth data under constant and changing temperature conditions were selected to obtain the primary model parameters, set up the secondary models, and apply them to predict the microbial growth and shelf life under fluctuating temperatures. When evaluated by general estimation behavior, bias factor, accuracy factor, and root-mean-square error, Huang’s model was comparable to Baranyi and Roberts’ model in the capability to estimate microbial growth under dynamic temperature conditions. Its simple form of single differential equation incorporating directly the growth rate and lag time may work as an advantage to be used in online shelf life estimation by using the electronic device.

Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

Energy Technology Data Exchange (ETDEWEB)

Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

2010-06-22

Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light

KAUST Repository

Xing, Defeng

2009-09-01

Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8-10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

Change in microbial communities in acetate- and glucose-fed microbial fuel cells in the presence of light

KAUST Repository

Xing, Defeng; Cheng, Shaoan; Regan, John M.; Logan, Bruce E.

2009-01-01

Power densities produced by microbial fuel cells (MFCs) in natural systems are changed by exposure to light through the enrichment of photosynthetic microorganisms. When MFCs with brush anodes were exposed to light (4000 lx), power densities increased by 8-10% for glucose-fed reactors, and 34% for acetate-fed reactors. Denaturing gradient gel electrophoresis (DGGE) profiles based on the 16S rRNA gene showed that exposure to high light levels changed the microbial communities on the anodes. Based on 16S rRNA gene clone libraries of light-exposed systems the anode communities using glucose were also significantly different than those fed acetate. Dominant bacteria that are known exoelectrogens were identified in the anode biofilm, including a purple nonsulfur (PNS) photosynthetic bacterium, Rhodopseudomonas palustris, and a dissimilatory iron-reducing bacterium, Geobacter sulfurreducens. Pure culture tests confirmed that PNS photosynthetic bacteria increased power production when exposed to high light intensities (4000 lx). These results demonstrate that power production and community composition are affected by light conditions as well as electron donors in single-chamber air-cathode MFCs. © 2009 Elsevier B.V. All rights reserved.

Evaluation of some physico-chemical properties of restructured trout and hake mince during cold gelation and chilled storage

DEFF Research Database (Denmark)

Moreno, H.M.; Javier Borderias, A.; Baron, Caroline

2010-01-01

Cold gelation was carried out on trout (Oncorhynchus mykiss) or on hake (Merluccius mertuccius) mince with or without addition of fish oil and using microbial transglutaminase (MTGase). Products were stored at 4 QC for 6 days and lipid oxidation, protein oxidation, texture, water binding capacity......, and colour were followed. Results indicated that MTGase was able to generate gels with good properties for both trout and hake. Gels prepared with trout were oxidised whilst gels prepared with hake were stable toward oxidation even in the presence of 5% fish oil. However, in the presence of oil...

11 Soil Microbial Biomass

African Journals Online (AJOL)

186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

Study of charge transfer reactions in a microbial fuel cell

Energy Technology Data Exchange (ETDEWEB)

Martin, E.; Savadogo, O. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. de Genie Chimique; National Research Council of Canada, Montreal, PQ (Canada). Biotechnology Research Inst.; Tartakovsky, B. [National Research Council of Canada, Montreal, PQ (Canada). Biotechnology Research Inst.

2008-07-01

Electron transfer reactions in a microbial fuel cell (MFC) were evaluated. The MFC was inoculated with anaerobic mesophilic sludge and operated with carbon felt, carbon cloth, and platinum (Pt) coated carbon cloth. The MFC was then fed with either acetate or glucose as a source of fuel and operated at a temperature of 25 degrees C and a pH of 7. Scanning electron microscopy (SEM) micrographs demonstrated that the micro-organisms colonized the anodes. Cyclic voltammetry and polarization tests were conducted using different fractions of the anodophilic biofilm in order to determine charge transfer routes. The study characterized the electron transfer mechanisms used by the exoelectrogenic micro-organisms to produce electricity. It was concluded that further research is needed to characterize reaction transfer routes. 2 refs., 1 fig.

MBGD update 2013: the microbial genome database for exploring the diversity of microbial world.

Science.gov (United States)

Uchiyama, Ikuo; Mihara, Motohiro; Nishide, Hiroyo; Chiba, Hirokazu

2013-01-01

The microbial genome database for comparative analysis (MBGD, available at http://mbgd.genome.ad.jp/) is a platform for microbial genome comparison based on orthology analysis. As its unique feature, MBGD allows users to conduct orthology analysis among any specified set of organisms; this flexibility allows MBGD to adapt to a variety of microbial genomic study. Reflecting the huge diversity of microbial world, the number of microbial genome projects now becomes several thousands. To efficiently explore the diversity of the entire microbial genomic data, MBGD now provides summary pages for pre-calculated ortholog tables among various taxonomic groups. For some closely related taxa, MBGD also provides the conserved synteny information (core genome alignment) pre-calculated using the CoreAligner program. In addition, efficient incremental updating procedure can create extended ortholog table by adding additional genomes to the default ortholog table generated from the representative set of genomes. Combining with the functionalities of the dynamic orthology calculation of any specified set of organisms, MBGD is an efficient and flexible tool for exploring the microbial genome diversity.

Spatial variation in microbial processes controlling carbon mineralization within soils and sediments

Energy Technology Data Exchange (ETDEWEB)

Fendorf, Scott [Stanford Univ., CA (United States); Kleber, Markus [Oregon State Univ., Corvallis, OR (United States); Nico, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-10-19

Soils have a defining role in global carbon cycling, having one of the largest dynamic stocks of C on earth—3300 Pg of C are stored in soils, which is three-times the amount stored in the atmosphere and more than the terrestrial land plants. An important control on soil organic matter (SOM) quantities is the mineralization rate. It is well recognized that the rate and extent of SOM mineralization is affected by climatic factors and mineral-organic matter associations. What remained elusive is to what extent constraints on microbial metabolism induced by the respiratory pathway, and specifically the electron acceptor in respiration, control overall rates of carbon mineralization in soils. Therefore, physical factors limiting oxygen diffusion such as soil texture and aggregate size (soil structure) may therefore be central controls on C mineralization rates. The goal of our research was therefore to determine if variations in microbial metabolic rates induced by anaerobic microsites in soils are a major control on SOM mineralization rates and thus storage. We performed a combination of laboratory experiments and field investigations will be performed to fulfill our research objectives. We used laboratory studies to examine fundamental factors of respiratory constraints (i.e., electron acceptor) on organic matter mineralization rates. We ground our laboratory studies with both manipulation of field samples and in-field measurements. Selection of the field sites is guided by variation in soil texture and structure while having (other environmental/soil factors constant. Our laboratory studies defined redox gradients and variations in microbial metabolism operating at the aggregate-scale (cm-scale) within soils using a novel constructed diffusion reactor. We further examined micro-scale variation in terminal electron accepting processes and resulting C mineralization rates within re-packed soils. A major outcome of our research is the ability to quantitatively place

Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?

Energy Technology Data Exchange (ETDEWEB)

White, G.J.

1996-08-01

Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus is on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern.

Microbial physiology-based model of ethanol metabolism in subsurface sediments

Science.gov (United States)

Jin, Qusheng; Roden, Eric E.

2011-07-01

A biogeochemical reaction model was developed based on microbial physiology to simulate ethanol metabolism and its influence on the chemistry of anoxic subsurface environments. The model accounts for potential microbial metabolisms that degrade ethanol, including those that oxidize ethanol directly or syntrophically by reducing different electron acceptors. Out of the potential metabolisms, those that are active in the environment can be inferred by fitting the model to experimental observations. This approach was applied to a batch sediment slurry experiment that examined ethanol metabolism in uranium-contaminated aquifer sediments from Area 2 at the U.S. Department of Energy Field Research Center in Oak Ridge, TN. According to the simulation results, complete ethanol oxidation by denitrification, incomplete ethanol oxidation by ferric iron reduction, ethanol fermentation to acetate and H 2, hydrogenotrophic sulfate reduction, and acetoclastic methanogenesis: all contributed significantly to the degradation of ethanol in the aquifer sediments. The assemblage of the active metabolisms provides a frame work to explore how ethanol amendment impacts the chemistry of the environment, including the occurrence and levels of uranium. The results can also be applied to explore how diverse microbial metabolisms impact the progress and efficacy of bioremediation strategies.

Transglutaminase 2 gene ablation protects against renal ischemic injury by blocking constant NF-κB activation

International Nuclear Information System (INIS)

Kim, Dae-Seok; Kim, Bora; Tahk, Hongmin; Kim, Dong-Hyun; Ahn, Eu-Ree; Choi, Changsun; Jeon, Yoon; Park, Seo Young; Lee, Ho; Oh, Seung Hyun; Kim, Soo-Youl

2010-01-01

Research highlights: → No acute renal tubular necrotic lesions were found in TGase2 -/- mice with ischemic kidney injury. → NF-κB activation is reduced in TGase2 -/- mice with ischemic kidney injury. → Hypoxic stress did not increase NF-κB activity in MEFs from TGase2 -/- mice. → COX-2 induction is suppressed in TGase2 -/- mice with ischemic kidney injury. -- Abstract: Transglutaminase 2 knockout (TGase2 -/- ) mice show significantly reduced inflammation with decreased myofibroblasts in a unilateral ureteral obstruction (UUO) model, but the mechanism remains to be clarified. Nuclear factor-κB (NF-κB) activation plays a major role in the progression of inflammation in an obstructive nephropathy model. However, the key factors extending the duration of NF-κB activation in UUO are not known. In several inflammatory diseases, we and others recently found that TGase 2 plays a key role in extending NF-κB activation, which contributes to the pathogenesis of disease. In the current study, we found that NF-κB activity in mouse embryogenic fibroblasts (MEFs) from TGase2 -/- mice remained at the control level while the NF-κB activity of wild-type (WT) MEFs was highly increased under hypoxic stress. Using the obstructive nephropathy model, we found that NF-κB activity remained at the control level in TGase2 -/- mouse kidney tissues, as measured by COX-2 expression, but was highly increased in WT tissues. We conclude that TGase 2 gene ablation reduces the duration of NF-κB activation in ischemic injury.

Serpentinization-Influenced Groundwater Harbors Extremely Low Diversity Microbial Communities Adapted to High pH.

Science.gov (United States)

Twing, Katrina I; Brazelton, William J; Kubo, Michael D Y; Hyer, Alex J; Cardace, Dawn; Hoehler, Tori M; McCollom, Tom M; Schrenk, Matthew O

2017-01-01

Serpentinization is a widespread geochemical process associated with aqueous alteration of ultramafic rocks that produces abundant reductants (H 2 and CH 4 ) for life to exploit, but also potentially challenging conditions, including high pH, limited availability of terminal electron acceptors, and low concentrations of inorganic carbon. As a consequence, past studies of serpentinites have reported low cellular abundances and limited microbial diversity. Establishment of the Coast Range Ophiolite Microbial Observatory (California, U.S.A.) allowed a comparison of microbial communities and physicochemical parameters directly within serpentinization-influenced subsurface aquifers. Samples collected from seven wells were subjected to a range of analyses, including solute and gas chemistry, microbial diversity by 16S rRNA gene sequencing, and metabolic potential by shotgun metagenomics, in an attempt to elucidate what factors drive microbial activities in serpentinite habitats. This study describes the first comprehensive interdisciplinary analysis of microbial communities in hyperalkaline groundwater directly accessed by boreholes into serpentinite rocks. Several environmental factors, including pH, methane, and carbon monoxide, were strongly associated with the predominant subsurface microbial communities. A single operational taxonomic unit (OTU) of Betaproteobacteria and a few OTUs of Clostridia were the almost exclusive inhabitants of fluids exhibiting the most serpentinized character. Metagenomes from these extreme samples contained abundant sequences encoding proteins associated with hydrogen metabolism, carbon monoxide oxidation, carbon fixation, and acetogenesis. Metabolic pathways encoded by Clostridia and Betaproteobacteria, in particular, are likely to play important roles in the ecosystems of serpentinizing groundwater. These data provide a basis for further biogeochemical studies of key processes in serpentinite subsurface environments.

Dual-Function Electrocatalytic and Macroporous Hollow-Fiber Cathode for Converting Waste Streams to Valuable Resources Using Microbial Electrochemical Systems

KAUST Repository

Katuri, Krishna; Kalathil, Shafeer; Ragab, Ala'a; Bian, Bin; AlQahtani, Manal Faisal; Pant, Deepak; Saikaly, Pascal

2018-01-01

Dual-function electrocatalytic and macroporous hollow-fiber cathodes are recently proposed as promising advanced material for maximizing the conversion of waste streams such as wastewater and waste CO2 to valuable resources (e.g., clean freshwater, energy, value-added chemicals) in microbial electrochemical systems. The first part of this progress report reviews recent developments in this type of cathode architecture for the simultaneous recovery of clean freshwater and energy from wastewater. Critical insights are provided on suitable materials for fabricating these cathodes, as well as addressing some challenges in the fabrication process with proposed strategies to overcome them. The second and complementary part of the progress report highlights how the unique features of this cathode architecture can solve one of the intrinsic bottlenecks (gas-liquid mass transfer limitation) in the application of microbial electrochemical systems for CO2 reduction to value-added products. Strategies to further improve the availability of CO2 to microbial catalysts on the cathode are proposed. The importance of understanding microbe-cathode interactions, as well as electron transfer mechanisms at the cathode-cell and cell-cell interface to better design dual-function macroporous hollow-fiber cathodes, is critically discussed with insights on how the choice of material is important in facilitating direct electron transfer versus mediated electron transfer.

Dual-Function Electrocatalytic and Macroporous Hollow-Fiber Cathode for Converting Waste Streams to Valuable Resources Using Microbial Electrochemical Systems

KAUST Repository

Katuri, Krishna

2018-04-30

Dual-function electrocatalytic and macroporous hollow-fiber cathodes are recently proposed as promising advanced material for maximizing the conversion of waste streams such as wastewater and waste CO2 to valuable resources (e.g., clean freshwater, energy, value-added chemicals) in microbial electrochemical systems. The first part of this progress report reviews recent developments in this type of cathode architecture for the simultaneous recovery of clean freshwater and energy from wastewater. Critical insights are provided on suitable materials for fabricating these cathodes, as well as addressing some challenges in the fabrication process with proposed strategies to overcome them. The second and complementary part of the progress report highlights how the unique features of this cathode architecture can solve one of the intrinsic bottlenecks (gas-liquid mass transfer limitation) in the application of microbial electrochemical systems for CO2 reduction to value-added products. Strategies to further improve the availability of CO2 to microbial catalysts on the cathode are proposed. The importance of understanding microbe-cathode interactions, as well as electron transfer mechanisms at the cathode-cell and cell-cell interface to better design dual-function macroporous hollow-fiber cathodes, is critically discussed with insights on how the choice of material is important in facilitating direct electron transfer versus mediated electron transfer.

In situ analysis of microbial reduction of a nitrate plume in Opalinus clay

International Nuclear Information System (INIS)

Bleyen, N.; Smets, S.; Valcke, E.; Albrecht, A.; De Canniere, P.; Schwyn, B.; Wittebroodt, C.

2012-01-01

nitrate and nitrite concentrations and pH, an on-line UV spectrophotometer and pH electrode are installed in the water circuit of one of the intervals. In a first series of tests, the biogeochemical evolution of the artificial Opalinus Clay pore water in the intervals was investigated after injection of low concentrations of nitrate or nitrate and acetate, simulating the BDP. The results of these tests indicate that microbial reduction of nitrate and nitrite can occur in the Opalinus Clay artificial water in the borehole, using acetate and/or clay components as electron donors. In these tests, nitrate was reduced to nitrite, ammonium and/or nitrogenous gases. Comparing the evolution in nitrate and nitrite concentrations in the absence or presence of acetate, clearly indicates faster reaction rates of microbial nitrate reduction when the system is fueled with acetate. When easily degradable organic compounds like acetate were added to the nitrate containing artificial pore water, these compounds were preferentially used as electron donors for nitrate reduction by heterotrophic microorganisms. Afterwards, alternative electron donors have been used originating either from the clay rock, e.g. pyrite, siderite, clay minerals, and/or dissolved natural organic matter, or from the stainless steel equipment, i.e. Fe 0 and/or Fe 2+ . Furthermore, high concentrations of nitrate reducing prokaryotes were detected after injection of the intervals with nitrate, indicating that the nitrate and nitrite reduction, observed during all tests, was microbially mediated. Based on the results of the microbiological analyses, these nitrate reducers have most likely been introduced during the first injection or installation of the downhole equipment. The nature of the nitrate reduction reaction prevailing in the system appears to be depending on the microbial populations active in the borehole and on the electron donors and carbon sources present in the interval. Furthermore, the history of the

Microbial activity on ligno cellulosic material

International Nuclear Information System (INIS)

Abdullah, N.; Wan, H.Y.; Jalaludin, S.

1991-01-01

Study of rumen bacteria and fungi colonizing rice straw was conducted in situ while the ability of rumen fungi to produce polysaccharides was investigated in vitro. In the microbial colonization study by electron microscopy, it was observed that rice straw fragments were heavily colonized by bacteria and fungi after 6 h of incubation in the rumen of cattle and buffaloes. Extensive degradation of cell walls was observed, particularly with rice fragments after 24 h of incubation. The fungal isolate from the rumen of cattle when in straw showed high activity of cellobiose, CMCase and FPase and to a lesser extent, xylanase and cellulase. (author)

Electron Transfer Strategies Regulate Carbonate Mineral and Micropore Formation

Science.gov (United States)

Zeng, Zhirui; Tice, Michael M.

2018-01-01

Some microbial carbonates are robust biosignatures due to their distinct morphologies and compositions. However, whether carbonates induced by microbial iron reduction have such features is unknown. Iron-reducing bacteria use various strategies to transfer electrons to iron oxide minerals (e.g., membrane-bound enzymes, soluble electron shuttles, nanowires, as well as different mechanisms for moving over or attaching to mineral surfaces). This diversity has the potential to create mineral biosignatures through manipulating the microenvironments in which carbonate precipitation occurs. We used Shewanella oneidensis MR-1, Geothrix fermentans, and Geobacter metallireducens GS-15, representing three different strategies, to reduce solid ferric hydroxide in order to evaluate their influence on carbonate and micropore formation (micro-size porosity in mineral rocks). Our results indicate that electron transfer strategies determined the morphology (rhombohedral, spherical, or long-chained) of precipitated calcium-rich siderite by controlling the level of carbonate saturation and the location of carbonate formation. Remarkably, electron transfer strategies also produced distinctive cell-shaped micropores in both carbonate and hydroxide minerals, thus producing suites of features that could potentially serve as biosignatures recording information about the sizes, shapes, and physiologies of iron-reducing organisms.

MATHEMATICAL MODELING OF THE ELECTRIC CURRENT GENERATION IN A MICROBIAL FUEL CELL INOCULATED WITH MARINE SEDIMENT

Directory of Open Access Journals (Sweden)

J. T. Teleken

Full Text Available Abstract Microbial fuel cells (MFC are electrochemical devices that utilize the ability of some microorganisms to oxidize organic matter and transfer electrons resulting from their metabolism to an insoluble acceptor. The goal of the present study was to model the kinetics of electrical current generation from an MFC inoculated with marine sediment. For this purpose, a differential equation system was used, including the Nernst-Monod relationship and Ohm's Law, to describe the microbial metabolism and the mechanism of extracellular electron transfer (EET, respectively. The experimental data obtained by cyclic voltammetry analysis were properly described by the model. It was concluded that marine microorganisms preferably use a direct mechanism of EET by means of nanowires to establish the electrochemical contact with the anode. The mathematical modeling could help understand MFC operation and, consequently, contribute to improving power generation from this source.

Microencapsulation of Lactobacillus rhamnosus GG by Transglutaminase Cross-Linked Soy Protein Isolate to Improve Survival in Simulated Gastrointestinal Conditions and Yoghurt.

Science.gov (United States)

Li, Chun; Wang, Chun-Ling; Sun, Yu; Li, Ai-Li; Liu, Fei; Meng, Xiang-Chen

2016-07-01

Microencapsulation is an effective way to improve the survival of probiotics in simulated gastrointestinal (GI) conditions and yoghurt. In this study, microencapsulation of Lactobacillus rhamnosus GG (LGG) was prepared by first cross-linking of soy protein isolate (SPI) using transglutaminase (TGase), followed by embedding the bacteria in cross-linked SPI, and then freeze-drying. The survival of microencapsulated LGG was evaluated in simulated GI conditions and yoghurt. The results showed that a high microencapsulation yield of 67.4% was obtained. The diameter of the microencapsulated LGG was in the range of 52.83 to 275.16 μm. Water activity did not differ between free and microencapsulated LGG after freeze-drying. The survival of microencapsulated LGG under simulated gastric juice (pH 2.5 and 3.6), intestinal juice (0.3% and 2% bile salt) and storage at 4 °C were significantly higher than that of free cells. The survival of LGG in TGase cross-linked SPI microcapsules was also improved to 14.5 ± 0.5% during storage in yoghurt. The microencapsulation of probiotics by TGase-treated SPI can be a suitable alternative to polysaccharide gelation technologies. © 2016 Institute of Food Technologists®

[Engineering issues of microbial ecology in space agriculture].

Science.gov (United States)

Yamashita, Masamichi; Ishikawa, Yoji; Oshima, Tairo

2005-03-01

Closure of the materials recycle loop for water-foods-oxygen is the primary purpose of space agriculture on Mars and Moon. A microbial ecological system takes a part of agriculture to process our metabolic excreta and inedible biomass and convert them to nutrients and soil substrate for cultivating plants. If we extend the purpose of space agriculture to the creation and control of a healthy and pleasant living environment, we should realize that our human body should not be sterilized but exposed to the appropriate microbial environment. We are proposing a use of hyper-thermophilic aerobic composting microbial ecology in space agriculture. Japan has a broad historical and cultural background on this subject. There had been agriculture that drove a closed loop of materials between consuming cities and farming villages in vicinity. Recent environmental problems regarding garbage collection and processing in towns have motivated home electronics companies to innovate "garbage composting" machines with bacterial technology. Based on those matured technology, together with new insights on microbiology and microbial ecology, we have been developing a conceptual design of space agriculture on Moon and Mars. There are several issues to be answered in order to prove effectiveness of the use of microbial systems in space. 1) Can the recycled nutrients, processed by the hyper-thermal aerobic composting microbial ecology, be formed in the physical and chemical state or configuration, with which plants can uptake those nutrients? A possibility of removing any major components of fertilizer from its recycle loop is another item to be evaluated. 2) What are the merits of forming soil microbial ecology around the root system of plants? This might be the most crucial question. Recent researches exhibit various mutually beneficial relationships among soil microbiota and plants, and symbiotic ecology in composting bacteria. It is essential to understand those features, and define

Microbial processes need to be addressed in a competent safety case

International Nuclear Information System (INIS)

Pedersen, Karsten; Hallbeck, Lotta

2014-01-01

Biological life processes should be separated from chemical inorganic processes. This is because most life processes are running along biochemical process pathways that are very different from those of inorganic chemical processes. Many chemical processes are restricted by various reaction barriers, e.g. the reduction process of sulphate to sulphide. They are, therefore, very slow or not possible at all under conditions typical for repositories for interim storage and long-term storage of radioactive wastes. Biological processes, consequently, include many reactions that do not occur in sterile, lifeless chemical systems. This is because life has the ability to over-run activation energy barriers and other energetic circumstances that block spontaneous chemical reactions. Life is possible from -20 deg. C up to around 113 deg. C, where all life processes stop. Life is also possible within a large pH range, from pH 1 up to at least pH 12.5. Finally, many processes overlap biology and chemistry such as sulphide and ferrous iron oxidation, which occur both as chemical and biological processes. Life processes in radioactive waste interim and long-term repositories will almost exclusively be under the control of micro-organisms. Microbial processes comprise red-ox reactions with decomposition and the production of organic molecules with different electron donors, energy sources and electron acceptors. Organic carbon in wastes, buffer materials and reduced inorganic molecules such as H2 from anaerobic corrosion processes and methane from geological sources are possible electron donors and energy sources for microbial processes. During the microbial oxidation of these energy sources, micro-organisms preferentially reduce electron acceptors in a particular order. First O 2 , and thereafter nitrate, manganese(IV), ferric iron, sulphate, sulphur and carbon dioxide are reduced. Simultaneously, fermentative processes lower pH and supply the metabolising micro-organisms with

Pulse electromagnetic fields enhance extracellular electron transfer in magnetic bioelectrochemical systems.

Science.gov (United States)

Zhou, Huihui; Liu, Bingfeng; Wang, Qisong; Sun, Jianmin; Xie, Guojun; Ren, Nanqi; Ren, Zhiyong Jason; Xing, Defeng

2017-01-01

Microbial extracellular electron transfer (EET) is essential in driving the microbial interspecies interaction and redox reactions in bioelectrochemical systems (BESs). Magnetite (Fe 3 O 4 ) and magnetic fields (MFs) were recently reported to promote microbial EET, but the mechanisms of MFs stimulation of EET and current generation in BESs are not known. This study investigates the behavior of current generation and EET in a state-of-the-art pulse electromagnetic field (PEMF)-assisted magnetic BES (PEMF-MBES), which was equipped with magnetic carbon particle (Fe 3 O 4 @N-mC)-coated electrodes. Illumina Miseq sequencing of 16S rRNA gene amplicons was also conducted to reveal the changes of microbial communities and interactions on the anode in response to magnetic field. PEMF had significant influences on current generation. When reactors were operated in microbial fuel cell (MFC) mode with pulse electromagnetic field (PEMF-MMFCs), power densities increased by 25.3-36.0% compared with no PEMF control MFCs (PEMF-OFF-MMFCs). More interestingly, when PEMF was removed, the power density dropped by 25.7%, while when PEMF was reintroduced, the value was restored to the previous level. Illumina sequencing of 16S rRNA gene amplicon and principal component analysis (PCA) based on operational taxonomic units (OTUs) indicate that PEMFs led to the shifts in microbial community and changes in species evenness that decreased biofilm microbial diversity. Geobacter spp. were found dominant in all anode biofilms, but the relative abundance in PEMF-MMFCs (86.1-90.0%) was higher than in PEMF-OFF-MMFCs (82.5-82.7%), indicating that the magnetic field enriched Geobacter on the anode. The current generation of Geobacter -inoculated microbial electrolysis cells (MECs) presented the same change regularity, the accordingly increase or decrease corresponding with switch of PEMF, which confirmed the reversible stimulation of PEMFs on microbial electron transfer. The pulse electromagnetic

Interpreting isotopic analyses of microbial sulfate reduction in oil reservoirs

Science.gov (United States)

Hubbard, C. G.; Engelbrektson, A. L.; Druhan, J. L.; Cheng, Y.; Li, L.; Ajo Franklin, J. B.; Coates, J. D.; Conrad, M. E.

2013-12-01

Microbial sulfate reduction in oil reservoirs is often associated with secondary production of oil where seawater (28 mM sulfate) is commonly injected to maintain reservoir pressure and displace oil. The hydrogen sulfide produced can cause a suite of operating problems including corrosion of infrastructure, health exposure risks and additional processing costs. We propose that monitoring of the sulfur and oxygen isotopes of sulfate can be used as early indicators that microbial sulfate reduction is occurring, as this process is well known to cause substantial isotopic fractionation. This approach relies on the idea that reactions with reservoir (iron) minerals can remove dissolved sulfide, thereby delaying the transport of the sulfide through the reservoir relative to the sulfate in the injected water. Changes in the sulfate isotopes due to microbial sulfate reduction may therefore be measurable in the produced water before sulfide is detected. However, turning this approach into a predictive tool requires (i) an understanding of appropriate fractionation factors for oil reservoirs, (ii) incorporation of isotopic data into reservoir flow and reactive transport models. We present here the results of preliminary batch experiments aimed at determining fractionation factors using relevant electron donors (e.g. crude oil and volatile fatty acids), reservoir microbial communities and reservoir environmental conditions (pressure, temperature). We further explore modeling options for integrating isotope data and discuss whether single fractionation factors are appropriate to model complex environments with dynamic hydrology, geochemistry, temperature and microbiology gradients.

Stability of U(VI) and Tc(VII) Reducing Microbial Communities to Environmental Perturbation: Development and Testing of a Thermodynamic Network Model

International Nuclear Information System (INIS)

McKinley, James P.; Istok, Jonathan

2005-01-01

Previously published research from in situ field experiments at the NABIR Field Research Center have shown that cooperative metabolism of denitrifiers and Fe(III)/sulfate reducers is essential for creating subsurface conditions favorable for U(VI) and Tc(VII) bioreduction (Istok et al., 2004). The overall goal of this project is to develop and test a thermodynamic network model for predicting the effects of substrate additions and environmental perturbations on the composition and functional stability of subsurface microbial communities. The overall scientific hypothesis is that a thermodynamic analysis of the energy-yielding reactions performed by broadly defined groups of microorganisms can be used to make quantitative and testable predictions of the change in microbial community composition that will occur when a substrate is added to the subsurface or when environmental conditions change. An interactive computer program was developed to calculate the overall growth equation and free energy yield for microorganisms that grow by coupling selected combinations of electron acceptor and electron donor half-reactions. Each group performs a specific function (e.g. oxidation of acetate coupled to reduction of nitrate); collectively the groups provide a theoretical description of the entire natural microbial community. The microbial growth data are combined with an existing thermodynamic data base for associated geochemical reactions and used to simulate the coupled microbial-geochemical response of a complex natural system to substrate addition or any other environmental perturbations

Detrital microbial community development and phosphorus dynamics in a stream ecosystem

Energy Technology Data Exchange (ETDEWEB)

Perkins, R.E.; Elwood, J.W.; Sayler, G.S.

1986-06-01

Detrital microbial community development and phosphorus dynamics in a lotic system were investigated in non-recirculating laboratory streams contains leaf detritus. Temporal patterns of microbial colonization, as determined by scanning electron microscopy, indicate leaf species dependency and that bacteria were the first colonizers followed by fungi. An extensive glycocalyx layer developed. Phosphorus incorporation rates of both the whole community and intracellular components were determined by time-course measurements of /sup 33/PO/sub 4/ or /sup 32/PO/sub 4/. Phosphorus turnover rates were determined by a sequential double-labeling procedure using /sup 33/PO/sub 4/ and /sup 32/PO/sub 4/, in which the microbiota were labeled with /sup 33/P until in isotopic equilibrium, then /sup 32/P was added. The turnover rate was determined by time-course measurements of the ratio /sup 32/P to /sup 33/P. Snail grazing resulted in an increase in phosphorus metabolism per unit microbial biomass; however, per unit area of leaf surface no increase was observed. Grazing also caused a two-fold reduction in microbial biomass. The results indicate that microbiota associated with decomposing leaves slowly recycle phosphorus, are slowly growing, and have a low metabolic activity. The spiraling length is shortened by microbiota on a short-term basis; however, it may increase on a long-term basis due to hydrological transport of detritus downstream.

Electron uptake by iron-oxidizing phototrophic bacteria

Energy Technology Data Exchange (ETDEWEB)

Bose, A; Gardel, EJ; Vidoudez, C; Parra, EA; Girguis, PR

2014-02-26

Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

Electron transfer capacity dependence of quinone-mediated Fe(III) reduction and current generation by Klebsiella pneumoniae L17.

Science.gov (United States)

Li, Xiaomin; Liu, Liang; Liu, Tongxu; Yuan, Tian; Zhang, Wei; Li, Fangbai; Zhou, Shungui; Li, Yongtao

2013-06-01

Quinone groups in exogenous electron shuttles can accelerate extracellular electron transfer (EET) from bacteria to insoluble terminal electron acceptors, such as Fe(III) oxides and electrodes, which are important in biogeochemical redox processes and microbial electricity generation. However, the relationship between quinone-mediated EET performance and electron-shuttling properties of the quinones remains incompletely characterized. This study investigates the effects of a series of synthetic quinones (SQs) on goethite reduction and current generation by a fermenting bacterium Klebsiella pneumoniae L17. In addition, the voltammetric behavior and electron transfer capacities (ETCs) of SQ, including electron accepting (EAC) and donating (EDC) capacities, is also examined using electrochemical methods. The results showed that SQ can significantly increase both the Fe(III) reduction rates and current outputs of L17. Each tested SQ reversibly accepted and donated electrons as indicated by the cyclic voltammograms. The EAC and EDC results showed that Carmine and Alizarin had low relative capacities of electron transfer, whereas 9,10-anthraquinone-2,6-disulfonic acid (AQDS), 2-hydroxy-1,4-naphthoquinone (2-HNQ), and 5-hydroxy-1,4-naphthoquinone (5-HNQ) showed stronger relative ETC, and 9,10-anthraquinone-2-carboxylic acid (AQC) and 9,10-anthraquinone-2-sulfonic acid (AQS) had high relative ETC. Enhancement of microbial goethite reduction kinetics and current outputs by SQ had a good linear relationship with their ETC, indicating that the effectiveness of quinone-mediated EET may be strongly dependent on the ETC of the quinones. Therefore, the presence of quinone compounds and fermenting microorganisms may increase the diversity of microbial populations that contribute to element transformation in natural environments. Moreover, ETC determination of different SQ would help to evaluate their performance for microbial EET under anoxic conditions. Copyright © 2013 Elsevier

Exoelectrogenic bacteria that power microbial fuel cells

KAUST Repository

Logan, Bruce E.

2009-01-01

There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

Exoelectrogenic bacteria that power microbial fuel cells

KAUST Repository

Logan, Bruce E.

2009-03-30

There has been an increase in recent years in the number of reports of microorganisms that can generate electrical current in microbial fuel cells. Although many new strains have been identified, few strains individually produce power densities as high as strains from mixed communities. Enriched anodic biofilms have generated power densities as high as 6.9 W per m2 (projected anode area), and therefore are approaching theoretical limits. To understand bacterial versatility in mechanisms used for current generation, this Progress article explores the underlying reasons for exocellular electron transfer, including cellular respiration and possible cell-cell communication.

Impact of natural organic matter coatings on the microbial reduction of iron oxides

Science.gov (United States)

Poggenburg, Christine; Mikutta, Robert; Schippers, Axel; Dohrmann, Reiner; Guggenberger, Georg

2018-03-01

Iron (Fe) oxyhydroxides are important constituents of the soil mineral phase known to stabilize organic matter (OM) under oxic conditions. In an anoxic milieu, however, these Fe-organic associations are exposed to microbial reduction, releasing OM into soil solution. At present, only few studies have addressed the influence of adsorbed natural OM (NOM) on the reductive dissolution of Fe oxyhydroxides. This study therefore examined the impact of both the composition and concentration of adsorbed NOM on microbial Fe reduction with regard to (i) electron shuttling, (ii) complexation of Fe(II,III), (iii) surface site coverage and/or pore blockage, and (iv) aggregation. Adsorption complexes with varying carbon loadings were synthesized using different Fe oxyhydroxides (ferrihydrite, lepidocrocite, goethite, hematite, magnetite) and NOM of different origin (extracellular polymeric substances from Bacillus subtilis, OM extracted from soil Oi and Oa horizons). The adsorption complexes were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), N2 gas adsorption, electrophoretic mobility and particle size measurements, and OM desorption. Incubation experiments under anaerobic conditions were conducted for 16 days comparing two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was assessed via XRD and FTIR. Microbial reduction of the pure Fe oxyhydroxides was controlled by the specific surface area (SSA) and solubility of the minerals. For Shewanella putrefaciens, the Fe reduction of adsorption complexes strongly correlated with the concentration of potentially usable electron-shuttling molecules for NOM concentrations <2 mg C L-1, whereas for Geobacter metallireducens, Fe reduction depended on the particle size and thus aggregation of the adsorption complexes. These diverging results suggest that

Insights into environmental controls on microbial communities in a continental serpentinite aquifer using a microcosm-based approach.

Science.gov (United States)

Crespo-Medina, Melitza; Twing, Katrina I; Kubo, Michael D Y; Hoehler, Tori M; Cardace, Dawn; McCollom, Tom; Schrenk, Matthew O

2014-01-01

Geochemical reactions associated with serpentinization alter the composition of dissolved organic compounds in circulating fluids and potentially liberate mantle-derived carbon and reducing power to support subsurface microbial communities. Previous studies have identified Betaproteobacteria from the order Burkholderiales and bacteria from the order Clostridiales as key components of the serpentinite-hosted microbiome, however there is limited knowledge of their metabolic capabilities or growth characteristics. In an effort to better characterize microbial communities, their metabolism, and factors limiting their activities, microcosm experiments were designed with fluids collected from several monitoring wells at the Coast Range Ophiolite Microbial Observatory (CROMO) in northern California during expeditions in March and August 2013. The incubations were initiated with a hydrogen atmosphere and a variety of carbon sources (carbon dioxide, methane, acetate, and formate), with and without the addition of nutrients and electron acceptors. Growth was monitored by direct microscopic counts; DNA yield and community composition was assessed at the end of the 3 month incubation. For the most part, results indicate that bacterial growth was favored by the addition of acetate and methane, and that the addition of nutrients and electron acceptors had no significant effect on microbial growth, suggesting no nutrient- or oxidant-limitation. However, the addition of sulfur amendments led to different community compositions. The dominant organisms at the end of the incubations were closely related to Dethiobacter sp. and to the family Comamonadaceae, which are also prominent in culture-independent gene sequencing surveys. These experiments provide one of first insights into the biogeochemical dynamics of the serpentinite subsurface environment and will facilitate experiments to trace microbial activities in serpentinizing ecosystems.

Microbial communities in bentonite formations and their interactions with uranium

International Nuclear Information System (INIS)

López-Fernández, Margarita; Fernández-Sanfrancisco, Omar; Moreno-García, Alberto; Martín-Sánchez, Inés; Sánchez-Castro, Iván; Merroun, Mohamed Larbi

2014-01-01

Highlights: • Microbial diversity of Spanish bentonites was studied. • High number of aerobe and facultative anaerobe microbes were isolated from bentonites. • Natural bentonite microbes are able to tolerate high U concentrations. • U is immobilized by the cells of the strain Rhodotorula mucilaginosa BII-R8 as U(VI) phosphates. - Abstract: A reliable performance assessment of deep geological disposal of nuclear waste depends on better knowledge of radionuclide interactions with natural microbes of geological formations (granitic rock, clay, salts) used to host these disposal systems. In Spain, clay deposits from Cabo de Gata region, Almeria, are investigated for this purpose. The present work characterizes the culture-dependent microbial diversity of two bentonite samples (BI and BII) recovered from Spanish clay deposits. The evaluation of aerobe and facultative anaerobe microbial populations shows the presence of a high number of cultivable bacteria (e.g. Stenotrophomonas, Micrococcus, Arthrobacter, Kocuria, Sphingomonas, Bacillus, Pseudomonas, etc.) affiliated to three phyla Proteobacteria, Actinobacteria, and Firmicutes. In addition, a pigmented yeast strain BII-R8 related to Rhodotorula mucilaginosa was also recovered from these formations. The minimal inhibitory concentrations of uranium for the growth of these natural isolates were found to range from 4 to 10.0 mM. For instance, strain R. mucilaginosa BII-R8 was shown to tolerate up to 8 mM of U. Flow cytometry studies indicated that the high U tolerance of this yeast isolate is a biologically mediated process. Microscopically dense intracellular and cell wall-bound precipitates were observed by Scanning Transmission Electron Microscopy-High-Angle Annular Dark-Field (STEM-HAADF). Energy Dispersive X-ray (EDX) element-distribution maps showed the presence of U and P within these accumulates, indicating the ability of cells to precipitate U as U(VI) phosphate minerals. Fundamental understanding of the

Microbial communities in bentonite formations and their interactions with uranium

Energy Technology Data Exchange (ETDEWEB)

López-Fernández, Margarita; Fernández-Sanfrancisco, Omar; Moreno-García, Alberto; Martín-Sánchez, Inés; Sánchez-Castro, Iván; Merroun, Mohamed Larbi, E-mail: merroun@ugr.es

2014-10-15

Highlights: • Microbial diversity of Spanish bentonites was studied. • High number of aerobe and facultative anaerobe microbes were isolated from bentonites. • Natural bentonite microbes are able to tolerate high U concentrations. • U is immobilized by the cells of the strain Rhodotorula mucilaginosa BII-R8 as U(VI) phosphates. - Abstract: A reliable performance assessment of deep geological disposal of nuclear waste depends on better knowledge of radionuclide interactions with natural microbes of geological formations (granitic rock, clay, salts) used to host these disposal systems. In Spain, clay deposits from Cabo de Gata region, Almeria, are investigated for this purpose. The present work characterizes the culture-dependent microbial diversity of two bentonite samples (BI and BII) recovered from Spanish clay deposits. The evaluation of aerobe and facultative anaerobe microbial populations shows the presence of a high number of cultivable bacteria (e.g. Stenotrophomonas, Micrococcus, Arthrobacter, Kocuria, Sphingomonas, Bacillus, Pseudomonas, etc.) affiliated to three phyla Proteobacteria, Actinobacteria, and Firmicutes. In addition, a pigmented yeast strain BII-R8 related to Rhodotorula mucilaginosa was also recovered from these formations. The minimal inhibitory concentrations of uranium for the growth of these natural isolates were found to range from 4 to 10.0 mM. For instance, strain R. mucilaginosa BII-R8 was shown to tolerate up to 8 mM of U. Flow cytometry studies indicated that the high U tolerance of this yeast isolate is a biologically mediated process. Microscopically dense intracellular and cell wall-bound precipitates were observed by Scanning Transmission Electron Microscopy-High-Angle Annular Dark-Field (STEM-HAADF). Energy Dispersive X-ray (EDX) element-distribution maps showed the presence of U and P within these accumulates, indicating the ability of cells to precipitate U as U(VI) phosphate minerals. Fundamental understanding of the

A theoretical reassessment of microbial maintenance and implications for microbial ecology modeling.

Science.gov (United States)

Wang, Gangsheng; Post, Wilfred M

2012-09-01

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a theoretical reassessment. We provided a rigorous proof that the true growth yield coefficient (Y(G)) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert (μ(max,H)) is higher than those in the other two models (μ(max,P) and μ(max,C)), and the difference is the physiological maintenance factor (m(q) = a); and (3) the overall maintenance coefficient (m(T)) is more sensitive to m(q) than to the specific growth rate (μ(G)) and Y(G). Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models. © This article is a US government work and is in the public domain in the USA.

Long distance electron transport in marine sediments: Microbial and geochemical implications

DEFF Research Database (Denmark)

Risgaard-Petersen, Nils; Larsen, Steffen; Pfeffer, Christian

and promotes the formation of Mg-calcite and iron oxides in the oxic zone. Oxygen seems to be the major electron acceptor, and more than 40% of the oxygen consumption in sediments can be driven by long distance electron transfer from distant electron donors. The major e-donor is sulfide, which is oxidized......Anaerobic oxidation of organic matter in marine sediment is traditionally considered to be coupled to oxygen reduction via a cascade of redox processes and transport of intermittent electron donors and acceptors. Electric currents have been found to shortcut this cascade and directly couple...... oxidation of sulphide centimeters down in marine sediment to the reduction of oxygen at the very surface1 . This electric coupling of spatially separated redox half-reactions seems to be mediated by centimeter long filamentous Desulfubulbus affiliated bacteria with morphological and ultra...

The Microbial DNA Index System (MiDIS): A tool for microbial pathogen source identification

Energy Technology Data Exchange (ETDEWEB)

Velsko, S. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2010-08-09

The microbial DNA Index System (MiDIS) is a concept for a microbial forensic database and investigative decision support system that can be used to help investigators identify the sources of microbial agents that have been used in a criminal or terrorist incident. The heart of the proposed system is a rigorous method for calculating source probabilities by using certain fundamental sampling distributions associated with the propagation and mutation of microbes on disease transmission networks. This formalism has a close relationship to mitochondrial and Y-chromosomal human DNA forensics, and the proposed decision support system is somewhat analogous to the CODIS and SWGDAM mtDNA databases. The MiDIS concept does not involve the use of opportunistic collections of microbial isolates and phylogenetic tree building as a basis for inference. A staged approach can be used to build MiDIS as an enduring capability, beginning with a pilot demonstration program that must meet user expectations for performance and validation before evolving into a continuing effort. Because MiDIS requires input from a a broad array of expertise including outbreak surveillance, field microbial isolate collection, microbial genome sequencing, disease transmission networks, and laboratory mutation rate studies, it will be necessary to assemble a national multi-laboratory team to develop such a system. The MiDIS effort would lend direction and focus to the national microbial genetics research program for microbial forensics, and would provide an appropriate forensic framework for interfacing to future national and international disease surveillance efforts.

Effects of Elevated Carbon Dioxide and Salinity on the Microbial Diversity in Lithifying Microbial Mats

Directory of Open Access Journals (Sweden)

Steven R. Ahrendt

2014-03-01

Full Text Available Atmospheric levels of carbon dioxide (CO2 are rising at an accelerated rate resulting in changes in the pH and carbonate chemistry of the world’s oceans. However, there is uncertainty regarding the impact these changing environmental conditions have on carbonate-depositing microbial communities. Here, we examine the effects of elevated CO2, three times that of current atmospheric levels, on the microbial diversity associated with lithifying microbial mats. Lithifying microbial mats are complex ecosystems that facilitate the trapping and binding of sediments, and/or the precipitation of calcium carbonate into organosedimentary structures known as microbialites. To examine the impact of rising CO2 and resulting shifts in pH on lithifying microbial mats, we constructed growth chambers that could continually manipulate and monitor the mat environment. The microbial diversity of the various treatments was compared using 16S rRNA gene pyrosequencing. The results indicated that elevated CO2 levels during the six month exposure did not profoundly alter the microbial diversity, community structure, or carbonate precipitation in the microbial mats; however some key taxa, such as the sulfate-reducing bacteria Deltasulfobacterales, were enriched. These results suggest that some carbonate depositing ecosystems, such as the microbialites, may be more resilient to anthropogenic-induced environmental change than previously thought.

MICROBIAL FUEL CELL

DEFF Research Database (Denmark)

2008-01-01

A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

A biomimetic porous hydrogel of gelatin and glycosaminoglycans cross-linked with transglutaminase and its application in the culture of hepatocytes

International Nuclear Information System (INIS)

De Colli, M; Massimi, M; Barbetta, A; Di Rosario, B L; Nardecchia, S; Dentini, M; Conti Devirgiliis, L

2012-01-01

The development of blended gelatin and glycosaminoglycan (GAG) scaffolds can potentially be used in many soft tissue engineering applications since these scaffolds mimic the structure and biological function of native extracellular matrix (ECM). In this study, we were able to obtain a gelatin–GAG scaffold by using a concentrated emulsion templating technique known as high internal phase emulsion (HIPE), in which a prevailing in volume organic phase is dispersed in the form of discrete droplets inside an aqueous solution of three biopolymers represented by gelatin, hyaluronic acid (HA) and chondroitin sulfate (CS) in the presence of a suitable surfactant. In order to preserve the bioactive potential of the biopolymers employed, the cross-linking procedure involved the use of transglutaminase (MTGase) that catalyzes the formation of covalent N-ε-(γ-glutamyl) lysine amide bonds. Since neither HA nor CS possess the necessary primary amino groups toward which MTGase is active, they were functionalized with the dipeptide glycine-lysine (GK). In this way the introduction of foreign cross-linking bridging units with an unpredictable biocompatibility was avoided. These enzymatic cross-linked gelatin–GAG scaffolds were tested in the culture of primary rat and C3A hepatocytes. Results underlined the good performance of this novel support in maintaining and promoting hepatocyte functions in vitro. (paper)

Molecular ecology of microbial mats

NARCIS (Netherlands)

Bolhuis, H.; Cretoiu, M.S.; Stal, L.J.

2014-01-01

Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep

Focusing on Environmental Biofilms With Variable-Pressure Scanning Electron Microscopy

Science.gov (United States)

Joubert, L.; Wolfaardt, G. M.; Du Plessis, K.

2006-12-01

Since the term biofilm has been coined almost 30 years ago, visualization has formed an integral part of investigations on microbial attachment. Electron microscopic (EM) biofilm studies, however, have been limited by the hydrated extracellular matrix which loses structural integrity with conventional preparative techniques, and under required high-vacuum conditions, resulting in a loss of information on spatial relationships and distribution of biofilm microbes. Recent advances in EM technology enable the application of Variable Pressure Scanning Electron Microscopy (VP SEM) to biofilms, allowing low vacuum and hydrated chamber atmosphere during visualization. Environmental biofilm samples can be viewed in situ, unfixed and fully hydrated, with application of gold-sputter-coating only, to increase image resolution. As the impact of microbial biofilms can be both hazardous and beneficial to man and his environment, recognition of biofilms as a natural form of microbial existence is needed to fully assess the potential role of microbial communities on technology. The integration of multiple techniques to elucidate biofilm processes has become imperative for unraveling complex phenotypic adaptations of this microbial lifestyle. We applied VP SEM as integrative technique with traditional and novel analytical techniques to (1)localize lignocellulosic microbial consortia applied for producing alternative bio-energy sources in the mining wastewater industry, (2) characterize and visualize wetland microbial communities in the treatment of winery wastewater, and (3)determine the impact of recombinant technology on yeast biofilm behavior. Visualization of microbial attachment to a lignocellulose substrate, and degradation of exposed plant tissue, gave insight into fiber degradation and volatile fatty acid production for biological sulphate removal from mining wastewater. Also, the 3D-architecture of complex biofilms developing in constructed wetlands was correlated with

Microbial Diversity in KURT Groundwater and Biomineralization Characteristics

International Nuclear Information System (INIS)

Roh, Yul; Rhee, Sung Keun; Oh, Jong Min; Park, Byung Jun

2009-03-01

The Underground Research Tunnel (URT) located in Korea Atomic Energy Research Institute (KAERI), Daejeon, South Korea was recently constructed as an experimental site to study radionuclide transport, biogeochemistry, radionuclide-mineral interactions for the geological disposal of high level nuclear waste. Groundwater sampled from URT was used to examine microbial diversity and to enrich metal reducing bacteria for studying microbe-metal interactions. Genomic analysis indicated that the groundwater contained diverse microorganisms such as metal reducers, metal oxidizers, anaerobic denitrifying bacteria, and bacteria for reductive dechlorination. Metal-reducing bacteria enriched from the groundwater was used to study metal reduction and biomineralization. The metal-reducing bacteria enriched with acetate or lactate as the electron donors showed the bacteria reduced Fe(III)-citrate, Fe(III) oxyhydroxides, Mn(IV) oxide, and Cr(VI) as the electron acceptors. Preliminary study indicated that the enriched bacteria were able to use glucose, lactate, acetate, and hydrogen as electron donors while reducing Fe(III)-citrate or Fe(III) oxyhydroxide as the electron acceptor. The bacteria exhibited diverse mineral precipitation capabilities including the formation of magnetite, siderite, and rhodochrosite. The results indicated that Fe(III)- and metal-reducing communities are present in URT at the KAERI

In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

International Nuclear Information System (INIS)

Baldwin, Brett R.; Peacock, Aaron D.; Resch, Charles T.; Arntzen, Evan; Smithgall, Amanda N.; Pfiffner, Susan; Gan, M.; McKinley, James P.; Long, Philip E.; White, David C.

2008-01-01

In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

Development of biologically modified anodes for energy harvesting using microbial fuel cells

Science.gov (United States)

Sumner, James J.; Ganguli, Rahul; Chmelka, Brad

2012-06-01

Biological fuel cells hold promise as an alternative energy source to batteries for unattended ground sensor applications due to the fact that they can be extremely long lived. This lifetime can be extended over batteries by scavenging fuel from the deployed environment. Microbial fuel cells (MFC) are one class of such sources that produce usable energy from small organic compounds (i.e. sugars, alcohols, organic acids, and biopolymers) which can be easily containerized or scavenged from the environment. The use of microorganisms as the anodic catalysts is what makes these systems unique from other biofuel cell designs. One of the main drawbacks of engineering a sensor system powered by an MFC is that power densities and current flux are extremely low in currently reported systems. The power density is limited by the mass transfer of the fuel source to the catalyst, the metabolism of the microbial catalysts and the electron transfer from the organism to the anode. This presentation will focus on the development of a new style of microbially-modified anodes which will increase power density to a level where a practical power source can be engineered. This is being achieved by developing a three dimensional matrix as an artificial, conductive biofilm. These artificial biofilms will allow the capture of a consortium of microbes designed for efficient metabolism of the available fuel source. Also it will keep the microbes close to the electrode allowing ready access by fuel and providing a low resistance passage of the liberated electrons from fuel oxidation.

In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

Energy Technology Data Exchange (ETDEWEB)

Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

2008-03-28

In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

Balancing cellular redox metabolism in microbial electrosynthesis and electro fermentation - A chance for metabolic engineering.

Science.gov (United States)

Kracke, Frauke; Lai, Bin; Yu, Shiqin; Krömer, Jens O

2018-01-01

More and more microbes are discovered that are capable of extracellular electron transfer, a process in which they use external electrodes as electron donors or acceptors for metabolic reactions. This feature can be used to overcome cellular redox limitations and thus optimizing microbial production. The technologies, termed microbial electrosynthesis and electro-fermentation, have the potential to open novel bio-electro production platforms from sustainable energy and carbon sources. However, the performance of reported systems is currently limited by low electron transport rates between microbes and electrodes and our limited ability for targeted engineering of these systems due to remaining knowledge gaps about the underlying fundamental processes. Metabolic engineering offers many opportunities to optimize these processes, for instance by genetic engineering of pathways for electron transfer on the one hand and target product synthesis on the other hand. With this review, we summarize the status quo of knowledge and engineering attempts around chemical production in bio-electrochemical systems from a microbe perspective. Challenges associated with the introduction or enhancement of extracellular electron transfer capabilities into production hosts versus the engineering of target compound synthesis pathways in natural exoelectrogens are discussed. Recent advances of the research community in both directions are examined critically. Further, systems biology approaches, for instance using metabolic modelling, are examined for their potential to provide insight into fundamental processes and to identify targets for metabolic engineering. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

Microbial biosensors for environmental monitoring

Directory of Open Access Journals (Sweden)

David VOGRINC

2015-12-01

Full Text Available Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.

Who's coming to dinner? Microbial phylogenetic analyses of various subsurface petroleum well environments for MEOR applications

Energy Technology Data Exchange (ETDEWEB)

Keeler, Sharon J.; Fallon, Robert; Jackson, Scott; Zhang, Shiping; Tomb, Jean-Francois; Miller, Mark A.; Rees, Bethany [Central Research and Development (Canada)

2011-07-01

This paper discussed the microbial phylogenetic analyses of various subsurface petroleum well environments for microbial-enhanced oil recovery (MEOR) applications. The objective is to add nutrients and microbes to injection water. Close to 47,000 compounds are present in petroleum and most of them are polyaromatic hydrocarbons (PAHs). Microbes that can predominate the biomass produced and the over all bioactivity are needed. Changing the electron acceptor modifies the microbial community. Characterization of microbial diversity in production water with two independent molecular methods is shown. The geology of well systems in North America was analyzed; the analyses and the results are given. Summarizing the North Slope reservoir system phylogenetics, it can be said that many genera found in association with other petroleum environments suggest they are autocthonous and transiently very high levels of acetate signify a mutual metabolic codependency on the amount of acetate present in the system.

Celiac anti-type 2 transglutaminase antibodies induce phosphoproteome modification in intestinal epithelial Caco-2 cells.

Directory of Open Access Journals (Sweden)

Gaetana Paolella

Full Text Available BACKGROUND: Celiac disease is an inflammatory condition of the small intestine that affects genetically predisposed individuals after dietary wheat gliadin ingestion. Type 2-transglutaminase (TG2 activity seems to be responsible for a strong autoimmune response in celiac disease, TG2 being the main autoantigen. Several studies support the concept that celiac anti-TG2 antibodies may contribute to disease pathogenesis. Our recent findings on the ability of anti-TG2 antibodies to induce a rapid intracellular mobilization of calcium ions, as well as extracellular signal-regulated kinase phosphorylation, suggest that they potentially act as signaling molecules. In line with this concept, we have investigated whether anti-TG2 antibodies can induce phosphoproteome modification in an intestinal epithelial cell line. METHODS AND PRINCIPAL FINDINGS: We studied phosphoproteome modification in Caco-2 cells treated with recombinant celiac anti-TG2 antibodies. We performed a two-dimensional electrophoresis followed by specific staining of phosphoproteins and mass spectrometry analysis of differentially phosphorylated proteins. Of 14 identified proteins (excluding two uncharacterized proteins, three were hypophosphorylated and nine were hyperphosphorylated. Bioinformatics analyses confirmed the presence of phosphorylation sites in all the identified proteins and highlighted their involvement in several fundamental biological processes, such as cell cycle progression, cell stress response, cytoskeletal organization and apoptosis. CONCLUSIONS: Identification of differentially phosphorylated proteins downstream of TG2-antibody stimulation suggests that in Caco-2 cells these antibodies perturb cell homeostasis by behaving as signaling molecules. We hypothesize that anti-TG2 autoantibodies may destabilize the integrity of the intestinal mucosa in celiac individuals, thus contributing to celiac disease establishment and progression. Since several proteins here

Development of carbon-11 labeled acryl amides for selective PET imaging of active tissue transglutaminase.

Science.gov (United States)

van der Wildt, Berend; Wilhelmus, Micha M M; Bijkerk, Jonne; Haveman, Lizeth Y F; Kooijman, Esther J M; Schuit, Robert C; Bol, John G J M; Jongenelen, Cornelis A M; Lammertsma, Adriaan A; Drukarch, Benjamin; Windhorst, Albert D

2016-04-01

Tissue transglutaminase (TG2) is a ubiquitously expressed enzyme capable of forming metabolically and mechanically stable crosslinks between the γ-carboxamide of a glutamine acyl-acceptor substrate and the ε-amino functionality of a lysine acyl-donor substrate resulting in protein oligomers. High TG2 crosslinking activity has been implicated in the pathogenesis of various diseases including celiac disease, cancer and fibrotic and neurodegenerative diseases. Development of a PET tracer specific for active TG2 provides a novel tool to further investigate TG2 biology in vivo in disease states. Recently, potent irreversible active site TG2 inhibitors carrying an acrylamide warhead were synthesized and pharmacologically characterized. Three of these inhibitors, compound 1, 2 and 3, were successfully radiolabeled with carbon-11 on the acrylamide carbonyl position using a palladium mediated [(11)C]CO aminocarbonylation reaction. Ex vivo biodistribution and plasma stability were evaluated in healthy Wistar rats. Autoradiography was performed on MDA-MB-231 tumor sections. [(11)C]1, -2 and -3 were obtained in decay corrected radiochemical yields of 38-55%. Biodistribution showed low uptake in peripheral tissues, with the exception of liver and kidney. Low brain uptake of <0.05% ID/g was observed. Blood plasma analysis demonstrated that [(11)C]1 and [(11)C]2 were rapidly metabolized, whereas [(11)C]3 was metabolized at a more moderate rate (63.2 ± 6.8 and 28.7 ± 10.8% intact tracer after 15 and 45 min, respectively). Autoradiography with [(11)C]3 on MDA-MB-231 tumor sections showed selective and specific binding of the radiotracer to the active state of TG2. Taken together, these results identify [(11)C]3 as the most promising of the three compounds tested for development as PET radiotracer for the in vivo investigation of TG2 activity. Copyright © 2016 Elsevier Inc. All rights reserved.

Development of a Photosynthetic Microbial Electrochemical Cell (PMEC Reactor Coupled with Dark Fermentation of Organic Wastes: Medium Term Perspectives

Directory of Open Access Journals (Sweden)

Samir Bensaid

2015-01-01

Full Text Available In this article the concept, the materials and the exploitation potential of a photosynthetic microbial electrochemical cell for the production of hydrogen driven by solar power are investigated. In a photosynthetic microbial electrochemical cell, which is based on photosynthetic microorganisms confined to an anode and heterotrophic bacteria confined to a cathode, water is split by bacteria hosted in the anode bioactive film. The generated electrons are conveyed through external “bio-appendages” developed by the bacteria to transparent nano-pillars made of indium tin oxide (ITO, Fluorine-doped tin oxide (FTO or other conducting materials, and then transferred to the cathode. On the other hand, the generated protons diffuse to the cathode via a polymer electrolyte membrane, where they are reduced by the electrons by heterotrophic bacteria growing attached to a similar pillared structure as that envisaged for the anode and supplemented with a specific low cost substrate (e.g., organic waste, anaerobic digestion outlet. The generated oxygen is released to the atmosphere or stored, while the produced pure hydrogen leaves the electrode through the porous layers. In addition, the integration of the photosynthetic microbial electrochemical cell system with dark fermentation as acidogenic step of anaerobic digester, which is able to produce additional H2, and the use of microbial fuel cell, feed with the residues of dark fermentation (mainly volatile fatty acids, to produce the necessary extra-bias for the photosynthetic microbial electrochemical cell is here analyzed to reveal the potential benefits to this novel integrated technology.

Methane emission in a specific riparian-zone sediment decreased with bioelectrochemical manipulation and corresponded to the microbial community dynamics

Directory of Open Access Journals (Sweden)

Elliot S. Friedman

2016-01-01

Full Text Available Dissimilatory metal-reducing bacteria are widespread in terrestrial ecosystems, especially in anaerobic soils and sediments. Thermodynamically, dissimilatory metal reduction is more favorable than sulfate reduction and methanogenesis but less favorable than denitrification and aerobic respiration. It is critical to understand the complex relationships, including the absence or presence of terminal electron acceptors, that govern microbial competition and coexistence in anaerobic soils and sediments, because subsurface microbial processes can effect greenhouse gas emissions from soils, possibly resulting in impacts at the global scale. Here, we elucidated the effect of an inexhaustible, ferrous-iron and humic-substance mimicking terminal electron acceptor by deploying potentiostatically poised electrodes in the sediment of a very specific stream riparian zone in Upstate New York state. At two sites within the same stream riparian zone during the course of six weeks in the spring of 2013, we measured CH4 and N2/N2O emissions from soil chambers containing either poised or unpoised electrodes, and we harvested biofilms from the electrodes to quantify microbial community dynamics. At the upstream site, which had a lower vegetation cover and highest soil temperatures, the poised electrodes inhibited CH4 emissions by ~45% (when normalized to remove temporal effects. CH4 emissions were not significantly impacted at the downstream site. N2/N2O emissions were generally low at both sites and were not impacted by poised electrodes. We did not find a direct link between bioelectrochemical treatment and microbial community membership; however, we did find a correspondence between environment/function and microbial community dynamics.

Synergistic microbial consortium for bioenergy generation from complex natural energy sources.

Science.gov (United States)

Wang, Victor Bochuan; Yam, Joey Kuok Hoong; Chua, Song-Lin; Zhang, Qichun; Cao, Bin; Chye, Joachim Loo Say; Yang, Liang

2014-01-01

Microbial species have evolved diverse mechanisms for utilization of complex carbon sources. Proper combination of targeted species can affect bioenergy production from natural waste products. Here, we established a stable microbial consortium with Escherichia coli and Shewanella oneidensis in microbial fuel cells (MFCs) to produce bioenergy from an abundant natural energy source, in the form of the sarcocarp harvested from coconuts. This component is mostly discarded as waste. However, through its usage as a feedstock for MFCs to produce useful energy in this study, the sarcocarp can be utilized meaningfully. The monospecies S. oneidensis system was able to generate bioenergy in a short experimental time frame while the monospecies E. coli system generated significantly less bioenergy. A combination of E. coli and S. oneidensis in the ratio of 1:9 (v:v) significantly enhanced the experimental time frame and magnitude of bioenergy generation. The synergistic effect is suggested to arise from E. coli and S. oneidensis utilizing different nutrients as electron donors and effect of flavins secreted by S. oneidensis. Confocal images confirmed the presence of biofilms and point towards their importance in generating bioenergy in MFCs.

Nanotechnology to rescue bacterial bidirectional extracellular electron transfer in bioelectrochemical systems

KAUST Repository

Kalathil, Shafeer

2016-03-17

An electrically active bacterium transports its metabolically generated electrons to insoluble substrates such as electrodes via a process known as extracellular electron transport (EET). Bacterial EET is a crucial process in the geochemical cycling of metals, bioremediation and bioenergy devices such as microbial fuel cells (MFCs). Recently, it has been found that electroactive bacteria can reverse their respiratory pathways by accepting electrons from a negatively poised electrode to produce high-value chemicals such as ethanol in a process termed as microbial electrosynthesis (MES). A poor electrical connection between bacteria and the electrode hinders the EET and MES processes significantly. Also, the bidirectional EET process is sluggish and needs to be improved drastically to extend its practical applications. Several attempts have been undertaken to improve the bidirectional EET by employing various advanced nanostructured materials such as carbon nanotubes and graphene. This review covers the recent progress in the bacterial bidirectional EET processes using advanced nanostructures in the light of current understandings of bacteria–nanomaterial interactions.

Hydrodynamics of microbial filter feeding

DEFF Research Database (Denmark)

Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

2017-01-01

Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude......; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet...

Secondary Electrons as an Energy Source for Life

Science.gov (United States)

Stelmach, Kamil B.; Neveu, Marc; Vick-Majors, Trista J.; Mickol, Rebecca L.; Chou, Luoth; Webster, Kevin D.; Tilley, Matt; Zacchei, Federica; Escudero, Cristina; Flores Martinez, Claudio L.; Labrado, Amanda; Fernández, Enrique J. G.

2018-01-01

Life on Earth is found in a wide range of environments as long as the basic requirements of a liquid solvent, a nutrient source, and free energy are met. Previous hypotheses have speculated how extraterrestrial microbial life may function, among them that particle radiation might power living cells indirectly through radiolytic products. On Earth, so-called electrophilic organisms can harness electron flow from an extracellular cathode to build biomolecules. Here, we describe two hypothetical mechanisms, termed "direct electrophy" and "indirect electrophy" or "fluorosynthesis," by which organisms could harness extracellular free electrons to synthesize organic matter, thus expanding the ensemble of potential habitats in which extraterrestrial organisms might be found in the Solar System and beyond. The first mechanism involves the direct flow of secondary electrons from particle radiation to a microbial cell to power the organism. The second involves the indirect utilization of impinging secondary electrons and a fluorescing molecule, either biotic or abiotic in origin, to drive photosynthesis. Both mechanisms involve the attenuation of an incoming particle's energy to create low-energy secondary electrons. The validity of the hypotheses is assessed through simple calculations showing the biomass density attainable from the energy supplied. Also discussed are potential survival strategies that could be used by organisms living in possible habitats with a plentiful supply of secondary electrons, such as near the surface of an icy moon. While we acknowledge that the only definitive test for the hypothesis is to collect specimens, we also describe experiments or terrestrial observations that could support or nullify the hypotheses.

Microbial Ecology of Soil Aggregation in Agroecosystems

Science.gov (United States)

Hofmockel, K. S.; Bell, S.; Tfailly, M.; Thompson, A.; Callister, S.

2017-12-01

Crop selection and soil texture influence the physicochemical attributes of the soil, which structures microbial communities and influences soil C cycling storage. At the molecular scale, microbial metabolites and necromass alter the soil environment, which creates feedbacks that influence ecosystem functions, including soil C accumulation. By integrating lab to field studies we aim to identify the molecules, organisms and metabolic pathways that control carbon cycling and stabilization in bioenergy soils. We investigated the relative influence of plants, microbes, and minerals on soil aggregate ecology at the Great Lakes Bioenergy Research experiment. Sites in WI and MI, USA have been in corn and switchgrass cropping systems for a decade. By comparing soil aggregate ecology across sites and cropping systems we are able to test the relative importance of plant, microbe, mineral influences on soil aggregate dynamics. Soil microbial communities (16S) differ in diversity and phylogeny among sites and cropping systems. FT-ICR MS revealed differences in the molecular composition of water-soluble fraction of soil organic matter for cropping systems and soil origin for both relative abundance of assigned formulas and biogeochemical classes of compounds. We found the degree of aggregation, measured by mean weighted diameter of aggregate fractions, is influenced by plant-soil interactions. Similarly, the proportion of soil aggregate fractions varied by both soil and plant factors. Differences in aggregation were reflected in differences in bacterial, but not fungal community composition across aggregate fractions, within each soil. Scanning electron microscopy revealed stark differences in mineral-organic interactions that influence the microbial niche and the accessibility of substrates within the soil. The clay soils show greater surface heterogeneity, enabling interactions with organic fraction of the soil. This is consistent with molecular data that reveal differences

Live microbial cells adsorb Mg2+ more effectively than lifeless organic matter

Science.gov (United States)

Qiu, Xuan; Yao, Yanchen; Wang, Hongmei; Duan, Yong

2018-03-01

The Mg2+ content is essential in determining different Mg-CaCO3 minerals. It has been demonstrated that both microbes and the organic matter secreted by microbes are capable of allocating Mg2+ and Ca2+ during the formation of Mg-CaCO3, yet detailed scenarios remain unclear. To investigate the mechanism that microbes and microbial organic matter potentially use to mediate the allocation of Mg2+ and Ca2+ in inoculating systems, microbial mats and four marine bacterial strains ( Synechococcus elongatus, Staphylococcus sp., Bacillus sp., and Desulfovibrio vulgaris) were incubated in artificial seawater media with Mg/Ca ratios ranging from 0.5 to 10.0. At the end of the incubation, the morphology of the microbial mats and the elements adsorbed on them were analyzed using scanning electronic microscopy (SEM) and energy diffraction spectra (EDS), respectively. The content of Mg2+ and Ca2+ adsorbed by the extracellular polysaccharide substances (EPS) and cells of the bacterial strains were analyzed with atomic adsorption spectroscopy (AAS). The functional groups on the surface of the cells and EPS of S. elongatus were estimated using automatic potentiometric titration combined with a chemical equilibrium model. The results show that live microbial mats generally adsorb larger amounts of Mg2+ than Ca2+, while this rarely is the case for autoclaved microbial mats. A similar phenomenon was also observed for the bacterial strains. The living cells adsorb more Mg2+ than Ca2+, yet a reversed trend was observed for EPS. The functional group analysis indicates that the cell surface of S. elongatus contains more basic functional groups (87.24%), while the EPS has more acidic and neutral functional groups (83.08%). These features may be responsible for the different adsorption behavior of Mg2+ and Ca2+ by microbial cells and EPS. Our work confirms the differential Mg2+ and Ca2+ mediation by microbial cells and EPS, which may provide insight into the processes that microbes use to

Flavin as an Indicator of the Rate-Limiting Factor for Microbial Current Production in Shewanella oneidensis MR-1

International Nuclear Information System (INIS)

Saito, Junki; Hashimoto, Kazuhito; Okamoto, Akihiro

2016-01-01

Microbial electrode catalysis such as microbial fuel cells or electrosynthesis involves electron exchange with the electrodes located at the cell exterior; i.e., extracellular electron transport (EET). Despite the vast amount of research on the kinetics of EET to optimize the catalysis rate, the relevance of other factors, including upstream metabolic reactions, has scarcely been investigated. Herein, we report an in vivo electrochemical assay to confirm whether EET limits anodic current production (j) for the lactate oxidation of Shewanella oneidensis MR-1. Addition of riboflavin, which specifically enhances the EET rate, increased j only in the early phase before j saturation. In contrast, when we removed a trace metal ion necessary for upstream reactions from the electrolyte, a significant decrease in j and the lactate consumption rate was observed only after j saturation. These data suggest that the limiting factor for j shifted from EET to upstream reactions, highlighting the general importance of enhancing, for example, microbial metabolism, especially for long-standing practical applications. Our concept to specifically control the rate of EET could be applicable to other bioelectrode catalysis systems as a strategy to monitor their rate-limiting factors.

Application of a global proteomic approach to archival precursor lesions: deleted in malignant brain tumors 1 and tissue transglutaminase 2 are upregulated in pancreatic cancer precursors

DEFF Research Database (Denmark)

Cheung, Wang; Darfler, Marlene M; Alvarez, Hector

2008-01-01

BACKGROUND: Pancreatic cancer is an almost uniformly fatal disease, and early detection is a critical determinant of improved survival. A variety of noninvasive precursor lesions of pancreatic adenocarcinoma have been identified, which provide a unique opportunity for intervention prior to onset ...... their overexpression in IPMNs. CONCLUSION: Global proteomics analysis using the Liquid Tissue workflow is a feasible approach for unbiased biomarker discovery in limited archival material, particularly applicable to precursor lesions of cancer......., and mass spectrometry to conduct a global proteomic analysis of an intraductal papillary mucinous neoplasm (IPMN). Tissue microarrays comprised of 38 IPMNs were used for validation of candidate proteins. RESULTS: The proteomic analysis of the IPMN Liquid Tissue lysate resulted in identification of 1......,534 peptides corresponding to 523 unique proteins. A subset of 25 proteins was identified that had previously been reported as upregulated in pancreatic cancer. Immunohistochemical analysis for two of these, deleted in malignant brain tumors 1 (DMBT1) and tissue transglutaminase 2 (TGM2), confirmed...

Microbial stratification and microbially catalyzed processes along a hypersaline chemocline

Science.gov (United States)

Hyde, A.; Joye, S. B.; Teske, A.

2017-12-01

Orca Basin is the largest deep hypersaline anoxic basin in the world, covering over 400 km2. Located at the bottom of the Gulf of Mexico, this body of water reaches depths of 200 meters and is 8 times denser (and more saline) than the overlying seawater. The sharp pycnocline prevents any significant vertical mixing and serves as a particle trap for sinking organic matter. These rapid changes in salinity, oxygen, organic matter, and other geochemical parameters present unique conditions for the microbial communities present. We collected samples in 10m intervals throughout the chemocline. After filtering the water, we used high-throughput bacterial and archaeal 16S rRNA gene sequencing to characterize the changing microbial community along the Orca Basin chemocline. The results reveal a dominance of microbial taxa whose biogeochemical function is entirely unknown. We then used metagenomic sequencing and reconstructed genomes for select samples, revealing the potential dominant metabolic processes in the Orca Basin chemocline. Understanding how these unique geochemical conditions shape microbial communities and metabolic capabilities will have implications for the ocean's biogeochemical cycles and the consequences of expanding oxygen minimum zones.

Tracing Biosignature Preservation of Geothermally Silicified Microbial Textures into the Geological Record.

Science.gov (United States)

Campbell, Kathleen A; Lynne, Bridget Y; Handley, Kim M; Jordan, Sacha; Farmer, Jack D; Guido, Diego M; Foucher, Frédéric; Turner, Susan; Perry, Randall S

2015-10-01

New Zealand and Argentine (Late Jurassic-Recent) siliceous hot-spring deposits (sinter) reveal preservation pathways of environmentally controlled, microbe-dominated sedimentary facies over geological time scales. Texturally distinctive, laminated to thinly layered, dense and vertically oriented, microtubular "palisade" fabric is common in low-temperature (geological events. A systematic approach was used to characterize palisade fabric in sinters of different ages to refine tools for recognizing biosignatures in extreme environments and to track their long-term preservation pathways into the geological record. Molecular techniques, scanning electron microscopy, Raman spectrometry, X-ray powder diffraction, petrography, and lipid biomarker analyses were applied. Results indicate that microbial communities vary at the micron scale and that early and rapid silicification is paramount to long-term preservation, especially where minimal postdepositional disturbance follows fossilization. Overall, it appears that the most robust biomarkers of fossil microbial activity in hot-spring deposits are their characteristic macro- and microtextures and laser micro-Raman identified carbon. Studies of Phanerozoic geothermal deposits with mineralized microbial components are relevant analogs for Precambrian geobiology because early life is commonly preserved as microbial microfossils and biofilms in silica, some of it hydrothermal in origin. Yet the diagenetic "movie" has already been run. Hence, studying younger sinters of a range of ages provides an opportunity to "play it again" and follow the varied influences on biosignatures into the deep-time geological record.

Microbial electrode sensor for alcohols

Energy Technology Data Exchange (ETDEWEB)

Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

1979-10-01

A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

Global microbialization of coral reefs.

Science.gov (United States)

Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

2016-04-25

Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

Electronic Nose Technology and its Applications

Directory of Open Access Journals (Sweden)

Esmaeil MAHMOUDI

2009-08-01

Full Text Available In the past decade, Electronic Nose instrumentation has generated much interest internationally for its potential to solve a wide variety of problems in fragrance and cosmetics production, food and beverages manufacturing, chemical engineering, environmental monitoring and more recently medical diagnostic, bioprocesses and clinical diagnostic plant diseases. This instrument measure electrical resistance changes generated by adsorption of volatiles to the surface of electro active- polymer coated sensor- unique digital electronic fingerprint of aroma derived from multi-sensor- responses to distinct mixture of microbial volatiles. Major advances in information and gas sensor technology could enhance the diagnostic power of future bio-electronic nose and facilitate global surveillance mode of disease control and management. Several dozen companies are now designed and selling electronic nose units globally for a wide variety of expending markets. The present review includes principles of electronic nose technology, biosensor structure and applications of electronic nose in many fields.

Carbon black as an alternative cathode material for electrical energy recovery and transfer in a microbial battery.

Science.gov (United States)

Zhang, Xueqin; Guo, Kun; Shen, Dongsheng; Feng, Huajun; Wang, Meizhen; Zhou, Yuyang; Jia, Yufeng; Liang, Yuxiang; Zhou, Mengjiao

2017-08-01

Rather than the conventional concept of viewing conductive carbon black (CB) to be chemically inert in microbial electrochemical cells (MECs), here we confirmed the redox activity of CB for its feasibility as an electron sink in the microbial battery (MB). Acting as the cathode of a MB, the solid-state CB electrode showed the highest electron capacity equivalent of 18.58 ± 0.46 C/g for the unsintered one and the lowest capacity of 2.29 ± 0.48 C/g for the one sintered under 100% N 2 atmosphere. The capacity vibrations of CBs were strongly in coincidence with the abundances of C=O moiety caused by different pretreatments and it implied one plausible mechanism based on CB's surface functionality for its electron capturing. Once subjected to electron saturation, CB could be completely regenerated by different strategies in terms of electrochemical discharging or donating electrons to biologically-catalyzed nitrate reduction. Surface characterization also revealed that CB's regeneration fully depended on the reversible shift of C=O moiety, further confirming the functionality-based mechanism for CB's feasibility as the role of MB's cathode. Moreover, resilience tests demonstrated that CB cathode was robust for the multi-cycles charging-discharging operations. These results imply that CB is a promising alternative material for the solid-state cathode in MBs.

Syntrophic Growth via Quinone-Mediated Interspecies Electron Transfer

Directory of Open Access Journals (Sweden)

Jessica A Smith

2015-02-01

Full Text Available The mechanisms by which microbial species exchange electrons are of interest because interspecies electron transfer can expand the metabolic capabilities of microbial communities. Previous studies with the humic substance analog anthraquinone-2,6-disulfonate (AQDS suggested that quinone-mediated interspecies electron transfer (QUIET is feasible, but it was not determined if sufficient energy is available from QUIET to support the growth of both species. Furthermore, there have been no previous studies on the mechanisms for the oxidation of anthrahydroquinone-2,6-disulfonate (AHQDS. A co-culture of Geobacter metallireducens and Geobacter sulfurreducens metabolized ethanol with the reduction of fumarate much faster in the presence of AQDS, and there was an increase in cell protein. G. sulfurreducens was more abundant, consistent with G. sulfurreducens obtaining electrons from acetate that G. metallireducens produced from ethanol, as well as from AHQDS. Cocultures initiated with a citrate synthase-deficient strain of G. sulfurreducens that was unable to use acetate as an electron donor also metabolized ethanol with the reduction of fumarate and cell growth, but acetate accumulated over time. G. sulfurreducens and G. metallireducens were equally abundant in these co-cultures reflecting the inability of the citrate synthase-deficient strain of G. sulfurreducens to metabolize acetate. Evaluation of the mechanisms by which G. sulfurreducens accepts electrons from AHQDS demonstrated that a strain deficient in outer-surface c-type cytochromes that are required for AQDS reduction was as effective at QUIET as the wild-type strain. Deletion of additional genes previously implicated in extracellular electron transfer also had no impact on QUIET. These results demonstrate that QUIET can yield sufficient energy to support the growth of both syntrophic partners, but that the mechanisms by which electrons are derived from extracellular hydroquinones require

GeoChip-based insights into the microbial functional gene repertoire of marine sponges (high microbial abundance, low microbial abundance) and seawater

KAUST Repository

Bayer, Kristina

2015-01-08

The GeoChip 4.2 gene array was employed to interrogate the microbial functional gene repertoire of sponges and seawater collected from the Red Sea and the Mediterranean. Complementary amplicon sequencing confirmed the microbial community composition characteristic of high microbial abundance (HMA) and low microbial abundance (LMA) sponges. By use of GeoChip, altogether 20 273 probes encoding for 627 functional genes and representing 16 gene categories were identified. Minimum curvilinear embedding analyses revealed a clear separation between the samples. The HMA/LMA dichotomy was stronger than any possible geographic pattern, which is shown here for the first time on the level of functional genes. However, upon inspection of individual genes, very few specific differences were discernible. Differences were related to microbial ammonia oxidation, ammonification, and archaeal autotrophic carbon fixation (higher gene abundance in sponges over seawater) as well as denitrification and radiation-stress-related genes (lower gene abundance in sponges over seawater). Except for few documented specific differences the functional gene repertoire between the different sources appeared largely similar. This study expands previous reports in that functional gene convergence is not only reported between HMA and LMA sponges but also between sponges and seawater.

GeoChip-based insights into the microbial functional gene repertoire of marine sponges (high microbial abundance, low microbial abundance) and seawater

KAUST Repository

Bayer, Kristina; Moitinho-Silva, Lucas; Brü mmer, Franz; Cannistraci, Carlo V.; Ravasi, Timothy; Hentschel, Ute

2015-01-01

The GeoChip 4.2 gene array was employed to interrogate the microbial functional gene repertoire of sponges and seawater collected from the Red Sea and the Mediterranean. Complementary amplicon sequencing confirmed the microbial community composition characteristic of high microbial abundance (HMA) and low microbial abundance (LMA) sponges. By use of GeoChip, altogether 20 273 probes encoding for 627 functional genes and representing 16 gene categories were identified. Minimum curvilinear embedding analyses revealed a clear separation between the samples. The HMA/LMA dichotomy was stronger than any possible geographic pattern, which is shown here for the first time on the level of functional genes. However, upon inspection of individual genes, very few specific differences were discernible. Differences were related to microbial ammonia oxidation, ammonification, and archaeal autotrophic carbon fixation (higher gene abundance in sponges over seawater) as well as denitrification and radiation-stress-related genes (lower gene abundance in sponges over seawater). Except for few documented specific differences the functional gene repertoire between the different sources appeared largely similar. This study expands previous reports in that functional gene convergence is not only reported between HMA and LMA sponges but also between sponges and seawater.

Autotrophic antimonate bio-reduction using hydrogen as the electron donor.

Science.gov (United States)

Lai, Chun-Yu; Wen, Li-Lian; Zhang, Yin; Luo, Shan-Shan; Wang, Qing-Ying; Luo, Yi-Hao; Chen, Ran; Yang, Xiaoe; Rittmann, Bruce E; Zhao, He-Ping

2016-01-01

Antimony (Sb), a toxic metalloid, is soluble as antimonate (Sb(V)). While bio-reduction of Sb(V) is an effective Sb-removal approach, its bio-reduction has been coupled to oxidation of only organic electron donors. In this study, we demonstrate, for the first time, the feasibility of autotrophic microbial Sb(V) reduction using hydrogen gas (H2) as the electron donor without extra organic carbon source. SEM and EDS analysis confirmed the production of the mineral precipitate Sb2O3. When H2 was utilized as the electron donor, the consortium was able to fully reduce 650 μM of Sb(V) to Sb(III) in 10 days, a rate comparable to the culture using lactate as the electron donor. The H2-fed culture directed a much larger fraction of it donor electrons to Sb(V) reduction than did the lactate-fed culture. While 98% of the electrons from H2 were used to reduce Sb(V) by the H2-fed culture, only 12% of the electrons from lactate was used to reduce Sb(V) by the lactate-fed culture. The rest of the electrons from lactate went to acetate and propionate through fermentation, to methane through methanogenesis, and to biomass synthesis. High-throughput sequencing confirmed that the microbial community for the lactate-fed culture was much more diverse than that for the H2-fed culture, which was dominated by a short rod-shaped phylotype of Rhizobium (α-Protobacteria) that may have been active in Sb(V) reduction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Electricity generation from tetrathionate in microbial fuel cells by acidophiles

International Nuclear Information System (INIS)

Sulonen, Mira L.K.; Kokko, Marika E.; Lakaniemi, Aino-Maija; Puhakka, Jaakko A.

2015-01-01

Highlights: • Electricity can be generated from tetrathionate in MFCs at pH below 2.5. • Tetrathionate disproportionated to sulfate and elemental sulfur. • Biohydrometallurgical process waters contained electrochemically active bacteria. • Acidithiobacillus spp. and Ferroplasma spp. were identified from the MFCs. - Abstract: Inorganic sulfur compounds, such as tetrathionate, are often present in mining process and waste waters. The biodegradation of tetrathionate was studied under acidic conditions in aerobic batch cultivations and in anaerobic anodes of two-chamber flow-through microbial fuel cells (MFCs). All four cultures originating from biohydrometallurgical process waters from multimetal ore heap bioleaching oxidized tetrathionate aerobically at pH below 3 with sulfate as the main soluble metabolite. In addition, all cultures generated electricity from tetrathionate in MFCs at pH below 2.5 with ferric iron as the terminal cathodic electron acceptor. The maximum current and power densities during MFC operation and in the performance analysis were 79.6 mA m −2 and 13.9 mW m −2 and 433 mA m −2 and 17.6 mW m −2 , respectively. However, the low coulombic efficiency (below 5%) indicates that most of the electrons were directed to other processes, such as aerobic oxidation of tetrathionate and unmeasured intermediates. The microbial community analysis revealed that the dominant species both in the anolyte and on the anode electrode surface of the MFCs were Acidithiobacillus spp. and Ferroplasma spp. This study provides a proof of concept that tetrathionate serves as electron donor for biological electricity production in the pH range of 1.2–2.5

Electricity generation from tetrathionate in microbial fuel cells by acidophiles

Energy Technology Data Exchange (ETDEWEB)

Sulonen, Mira L.K., E-mail: mira.sulonen@tut.fi; Kokko, Marika E.; Lakaniemi, Aino-Maija; Puhakka, Jaakko A.

2015-03-02

Highlights: • Electricity can be generated from tetrathionate in MFCs at pH below 2.5. • Tetrathionate disproportionated to sulfate and elemental sulfur. • Biohydrometallurgical process waters contained electrochemically active bacteria. • Acidithiobacillus spp. and Ferroplasma spp. were identified from the MFCs. - Abstract: Inorganic sulfur compounds, such as tetrathionate, are often present in mining process and waste waters. The biodegradation of tetrathionate was studied under acidic conditions in aerobic batch cultivations and in anaerobic anodes of two-chamber flow-through microbial fuel cells (MFCs). All four cultures originating from biohydrometallurgical process waters from multimetal ore heap bioleaching oxidized tetrathionate aerobically at pH below 3 with sulfate as the main soluble metabolite. In addition, all cultures generated electricity from tetrathionate in MFCs at pH below 2.5 with ferric iron as the terminal cathodic electron acceptor. The maximum current and power densities during MFC operation and in the performance analysis were 79.6 mA m{sup −2} and 13.9 mW m{sup −2} and 433 mA m{sup −2} and 17.6 mW m{sup −2}, respectively. However, the low coulombic efficiency (below 5%) indicates that most of the electrons were directed to other processes, such as aerobic oxidation of tetrathionate and unmeasured intermediates. The microbial community analysis revealed that the dominant species both in the anolyte and on the anode electrode surface of the MFCs were Acidithiobacillus spp. and Ferroplasma spp. This study provides a proof of concept that tetrathionate serves as electron donor for biological electricity production in the pH range of 1.2–2.5.

New microbial resource: microbial diversity, function and dynamics in Chinese liquor starter.

Science.gov (United States)

Huang, Yuhong; Yi, Zhuolin; Jin, Yanling; Zhao, Yonggui; He, Kaize; Liu, Dayu; Zhao, Dong; He, Hui; Luo, Huibo; Zhang, Wenxue; Fang, Yang; Zhao, Hai

2017-11-06

Traditional Chinese liquor (Baijiu) solid state fermentation technology has lasted for several thousand years. The microbial communities that enrich in liquor starter are important for fermentation. However, the microbial communities are still under-characterized. In this study, 454 pyrosequencing technology was applied to comprehensively analyze the microbial diversity, function and dynamics of two most-consumed liquor starters (Jiang- and Nong-flavor) during production. In total, 315 and 83 bacterial genera and 72 and 47 fungal genera were identified in Jiang- and Nong-flavor liquor starter, respectively. The relatively high diversity was observed when the temperature increased to 70 and 62 °C for Jiang- and Nong-flavor liquor starter, respectively. Some thermophilic fungi have already been isolated. Microbial communities that might contribute to ethanol fermentation, saccharification and flavor development were identified and shown to be core communities in correlation-based network analysis. The predictively functional profile of bacterial communities showed significant difference in energy, carbohydrate and amino acid metabolism and the degradation of aromatic compounds between the two kinds of liquor starters. Here we report these liquor starters as a new functionally microbial resource, which can be used for discovering thermophilic and aerobic enzymes and for food and feed preservation.

The maturing of microbial ecology.

Science.gov (United States)

Schmidt, Thomas M

2006-09-01

A.J. Kluyver and C.B. van Niel introduced many scientists to the exceptional metabolic capacity of microbes and their remarkable ability to adapt to changing environments in The Microbe's Contribution to Biology. Beyond providing an overview of the physiology and adaptability of microbes, the book outlined many of the basic principles for the emerging discipline of microbial ecology. While the study of pure cultures was highlighted, provided a unifying framework for understanding the vast metabolic potential of microbes and their roles in the global cycling of elements, extrapolation from pure cultures to natural environments has often been overshadowed by microbiologists inability to culture many of the microbes seen in natural environments. A combination of genomic approaches is now providing a culture-independent view of the microbial world, revealing a more diverse and dynamic community of microbes than originally anticipated. As methods for determining the diversity of microbial communities become increasingly accessible, a major challenge to microbial ecologists is to link the structure of natural microbial communities with their functions. This article presents several examples from studies of aquatic and terrestrial microbial communities in which culture and culture-independent methods are providing an enhanced appreciation for the microbe's contribution to the evolution and maintenance of life on Earth, and offers some thoughts about the graduate-level educational programs needed to enhance the maturing field of microbial ecology.

The nanostructure of microbially-reduced graphene oxide fosters thick and highly-performing electrochemically-active biofilms

Science.gov (United States)

Virdis, Bernardino; Dennis, Paul G.

2017-07-01

Biofilms of electrochemically-active organisms are used in microbial electrochemical technologies (METs) to catalyze bioreactions otherwise not possible at bare electrodes. At present, however, achievable current outputs are still below levels considered sufficient for economic viability of large-scale METs implementations. Here, we report three-dimensional, self-aggregating biofilm composites comprising of microbial cells embedded with microbially-reduced graphene oxide (rGO) nanoparticles to form a thick macro-porous network with superior electrochemical properties. In the presence of metabolic substrate, these hybrid biofilms are capable of producing up to five times more catalytic current than the control biofilms. Cyclic voltammetry, linear sweep voltammetry, and electrochemical impedance spectroscopy, show that in spite of the increased thickness, the biofilms amended with GO display lower polarization/charge transfer resistance compared to the controls, which we ascribe to the incorporation of rGO into the biofilms, which (1) promotes fast electron transfer, yet conserving a macroporous structure that allows free diffusion of reactants and products, and (2) enhances the interfacial dynamics by allowing a higher load of microbial cells per electrode surface area. These results suggest an easy-to-apply and cost-effective method to produce high-performing electrochemically-active biofilms in situ.

In-Drift Microbial Communities

Energy Technology Data Exchange (ETDEWEB)

D. Jolley

2000-11-09

As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

In-Drift Microbial Communities

International Nuclear Information System (INIS)

Jolley, D.

2000-01-01

As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses

Microbial synthesis of poly(epsilon-lysine) and its various applications.

Science.gov (United States)

Shih, Ing-Lung; Shen, Ming-Haw; Van, Yi-Tsong

2006-06-01

This review article deals with the microbial synthesis, physiochemical properties, and potential applications of poly-epsilon-lysine (epsilon-PL), which is a naturally occurring biomaterial that is water soluble, biodegradable, edible and non-toxic toward humans and the environment. The potential applications of epsilon-PL as food preservatives, emulsifying agent, dietary agent, biodegradable fibers, highly water absorbable hydrogels, drug carriers, anticancer agent enhancer, biochip coatings in the fields of food, medicine, agriculture and electronics are also discussed in this review.

Generation of Electricity and Analysis of Microbial Communities in Wheat Straw Biomass-Powered Microbial Fuel Cells

DEFF Research Database (Denmark)

Zhang, Yifeng; Min, Booki; Huang, L.

2009-01-01

Electricity generation from wheat straw hydrolysate and the microbial ecology of electricity producing microbial communities developed in two chamber microbial fuel cells (MFCs) were investigated. Power density reached 123 mW/m2 with an initial hydrolysate concentration of 1000 mg-COD/L while...

Microbial interspecies electron transfer via electric currents through conductive minerals

Science.gov (United States)

Kato, Souichiro; Hashimoto, Kazuhito; Watanabe, Kazuya

2012-01-01

In anaerobic biota, reducing equivalents (electrons) are transferred between different species of microbes [interspecies electron transfer (IET)], establishing the basis of cooperative behaviors and community functions. IET mechanisms described so far are based on diffusion of redox chemical species and/or direct contact in cell aggregates. Here, we show another possibility that IET also occurs via electric currents through natural conductive minerals. Our investigation revealed that electrically conductive magnetite nanoparticles facilitated IET from Geobacter sulfurreducens to Thiobacillus denitrificans, accomplishing acetate oxidation coupled to nitrate reduction. This two-species cooperative catabolism also occurred, albeit one order of magnitude slower, in the presence of Fe ions that worked as diffusive redox species. Semiconductive and insulating iron-oxide nanoparticles did not accelerate the cooperative catabolism. Our results suggest that microbes use conductive mineral particles as conduits of electrons, resulting in efficient IET and cooperative catabolism. Furthermore, such natural mineral conduits are considered to provide ecological advantages for users, because their investments in IET can be reduced. Given that conductive minerals are ubiquitously and abundantly present in nature, electric interactions between microbes and conductive minerals may contribute greatly to the coupling of biogeochemical reactions. PMID:22665802

Novel Microbial Electrochemical Technologies and Microorganisms for Power Generation and Desalination

KAUST Repository

Chehab, Noura A.

2014-12-01

Global increases in water demand and decreases in both the quantity and quality of fresh water resources have served as the major driving forces to develop sustainable use of water resources. One viable alternative is to explore non-traditional (impaired quality) water sources such as wastewater and seawater. The current paradigm for wastewater treatment is based on technologies that are energy intensive and fail to recover the potential resources (water and energy) in wastewater. Also, conventional desalination technologies like reverse osmosis (RO) are energy intensive. Therefore, there is a need for the development of sustainable wastewater treatment and desalination technologies for practical applications. Processes based on microbial electrochemical technologies (METs) such as microbial fuel cells (MFCs), microbial electrolysis cells (MECs) and microbial desalination cells (MDCs) hold promise for the treatment of wastewater with recovery of the inherent energy, and MDCs could be used for both desalination of seawater and energy recovery. METs use anaerobic bacteria, referred to as exoelectrogens, that are capable of transferring electrons exogenously to convert soluble organic matter present in the wastewater directly into an electrical current to produce electrical power (MFC and MDC) or biogas (MEC). In my dissertation, I investigated the three types of METs mentioned above to: 1) have a better insight on the effect of 4 oxygen intrusion on the microbial community structure and performance of air-cathode MFCs; 2) improve the desalination efficiency of air-cathode MDCs using ion exchange resins (IXRs); and 3) enrich for extremophilic exoelectrogens from the Red Sea brine pool using MECs. The findings from these studies can shape further research aimed at developing more efficient air-cathode MFCs for practical applications, a more efficient integrated IXRMDC configuration that can be used as a pre-treatment to RO, and exploring extreme environments as a

Characterization of plasma-polymerized 4-vinyl pyridine with silver nanoparticies on poly(ethylene terephthalate) film for anti-microbial properties

DEFF Research Database (Denmark)

Jiang, J.; Winther-Jensen, Bjørn; Kjær, Erik Michael

2006-01-01

scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Different thicknesses Of poly(4-vinyl pyridine) coating under different plasma polymerization conditions were studied. Silver nanoparticles with diameter around 50nm deposit were precipitated...... on the poly(4-vinyl pyridine) coating by UV irradiation in Silver nitride water solution, in order to enhance the anti-microbial properties. Different kinds of modified PET films were tested for anti-microbial properties against yeast (Debaryomyces hansenii) by using microbiological analyser mu-4200...

[Potential Carbon Fixation Capability of Non-photosynthetic Microbial Community at Different Depth of the South China Sea and Its Response to Different Electron Donors].

Science.gov (United States)

Fang, Feng; Wang, Lei; Xi, Xue-fei; Hu, Jia-jun; Fu, Xiao-hua; Lu, Bing; Xu, Dian-sheng