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Christiane Gruber-Dorninger
BIOMIN Research Center, BIOMIN Holding GmbH, 3430 Tulln, Austria

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Journal article
Published: 22 January 2021 in Toxins
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The mycotoxin zearalenone (ZEN) is a frequent contaminant of animal feed and is well known for its estrogenic effects in animals. Cattle are considered less sensitive to ZEN than pigs. However, ZEN has previously been shown to be converted to the highly estrogenic metabolite α-zearalenol (α-ZEL) in rumen fluid in vitro. Here, we investigate the metabolism of ZEN in the reticulorumen of dairy cows. To this end, rumen-fistulated non-lactating Holstein Friesian cows (n = 4) received a one-time oral dose of ZEN (5 mg ZEN in 500 g concentrate feed) and the concentrations of ZEN and ZEN metabolites were measured in free rumen liquid from three reticulorumen locations (reticulum, ventral sac and dorsal mat layer) during a 34-h period. In all three locations, α-ZEL was the predominant ZEN metabolite and β-zearalenol (β-ZEL) was detected in lower concentrations. ZEN, α-ZEL and β-ZEL were eliminated from the ventral sac and reticulum within 34 h, yet low concentrations of ZEN and α-ZEL were still detected in the dorsal mat 34 h after ZEN administration. In a second step, we investigated the efficacy of the enzyme zearalenone hydrolase ZenA (EC 3.1.1.-, commercial name ZENzyme®, BIOMIN Holding GmbH, Getzersdorf, Austria) to degrade ZEN to the non-estrogenic metabolite hydrolyzed zearalenone (HZEN) in the reticulorumen in vitro and in vivo. ZenA showed a high ZEN-degrading activity in rumen fluid in vitro. When ZenA was added to ZEN-contaminated concentrate fed to rumen-fistulated cows (n = 4), concentrations of ZEN, α-ZEL and β-ZEL were significantly reduced in all three reticulorumen compartments compared to administration of ZEN-contaminated concentrate without ZenA. Upon ZenA administration, degradation products HZEN and decarboxylated HZEN were detected in the reticulorumen. In conclusion, endogenous metabolization of ZEN in the reticulorumen increases its estrogenic potency due to the formation of α-ZEL. Our results suggest that application of zearalenone hydrolase ZenA as a feed additive may be a promising strategy to counteract estrogenic effects of ZEN in cattle.

ACS Style

Christiane Gruber-Dorninger; Johannes Faas; Barbara Doupovec; Markus Aleschko; Christian Stoiber; Andreas Höbartner-Gußl; Karin Schöndorfer; Manuela Killinger; Qendrim Zebeli; Dian Schatzmayr. Metabolism of Zearalenone in the Rumen of Dairy Cows with and without Application of a Zearalenone-Degrading Enzyme. Toxins 2021, 13, 84 .

AMA Style

Christiane Gruber-Dorninger, Johannes Faas, Barbara Doupovec, Markus Aleschko, Christian Stoiber, Andreas Höbartner-Gußl, Karin Schöndorfer, Manuela Killinger, Qendrim Zebeli, Dian Schatzmayr. Metabolism of Zearalenone in the Rumen of Dairy Cows with and without Application of a Zearalenone-Degrading Enzyme. Toxins. 2021; 13 (2):84.

Chicago/Turabian Style

Christiane Gruber-Dorninger; Johannes Faas; Barbara Doupovec; Markus Aleschko; Christian Stoiber; Andreas Höbartner-Gußl; Karin Schöndorfer; Manuela Killinger; Qendrim Zebeli; Dian Schatzmayr. 2021. "Metabolism of Zearalenone in the Rumen of Dairy Cows with and without Application of a Zearalenone-Degrading Enzyme." Toxins 13, no. 2: 84.

Journal article
Published: 01 August 2020 in Toxins
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Mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) can negatively affect pig health. However, little is known about their effects on boar semen. We assessed the individual and combined effects of DON and ZEN on boar semen in vitro. In a pretrial, we determined the minimum dose (MiD) of each mycotoxin that induces a significant alteration of sperm progressive motility, as investigated using computer-assisted semen analysis (CASA). In the main trial, the individual and combined effects of each mycotoxin’s MiD on sperm motility and kinetics (CASA analysis), morphology (SpermBlue staining), viability (calcein-propidium iodide staining), membrane functional status (hypoosmotic swelling test), and chromatin integrity (acridine orange staining) were analyzed. Pretrial results suggested a MiD of 50.6 μM and 62.8 μM for DON and ZEN, respectively. In the main trial, DON and ZEN administered at MiD significantly affected CASA parameters (e.g., increase of immotile spermatozoa, reduction of progressive motile spermatozoa), decreased sperm viability, and affected sperm morphology (head abnormalities) and membrane functional status. DON and ZEN showed less than additive effects on most parameters tested and a synergistic effect on viability and on two CASA parameters. In conclusion, DON and ZEN showed individual and combined toxic effects on boar semen in vitro.

ACS Style

Panagiotis Tassis; Ioannis Tsakmakidis; Veronika Nagl; Nicole Reisinger; Eleni Tzika; Christiane Gruber-Dorninger; Ilias Michos; Nikolaos Mittas; Athina Basioura; Dian Schatzmayr. Individual and Combined In Vitro Effects of Deoxynivalenol and Zearalenone on Boar Semen. Toxins 2020, 12, 495 .

AMA Style

Panagiotis Tassis, Ioannis Tsakmakidis, Veronika Nagl, Nicole Reisinger, Eleni Tzika, Christiane Gruber-Dorninger, Ilias Michos, Nikolaos Mittas, Athina Basioura, Dian Schatzmayr. Individual and Combined In Vitro Effects of Deoxynivalenol and Zearalenone on Boar Semen. Toxins. 2020; 12 (8):495.

Chicago/Turabian Style

Panagiotis Tassis; Ioannis Tsakmakidis; Veronika Nagl; Nicole Reisinger; Eleni Tzika; Christiane Gruber-Dorninger; Ilias Michos; Nikolaos Mittas; Athina Basioura; Dian Schatzmayr. 2020. "Individual and Combined In Vitro Effects of Deoxynivalenol and Zearalenone on Boar Semen." Toxins 12, no. 8: 495.

Journal article
Published: 27 June 2019 in Toxins
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Mycotoxins contaminating animal feed can exert toxic effects in animals and be transferred into animal products. Therefore, mycotoxin occurrence in feed should be monitored. To this end, we performed a large-scale global survey of mycotoxin contamination in feed and assessed regional differences and year-to-year variation of mycotoxin occurrence. Concentrations of aflatoxin B1, zearalenone, fumonisins, ochratoxin A, deoxynivalenol, and T-2 toxin were analyzed in 74,821 samples of feed and feed raw materials (e.g., maize, wheat, soybean) collected from 100 countries from 2008 to 2017. In total, 88% of the samples were contaminated with at least one mycotoxin. Mycotoxin occurrence showed distinct regional trends and climate was a key determinant governing these trends. In most regions, the majority of samples complied with maximum levels and guidance values for mycotoxins in animal feed that are in effect in the European Union. However, 41.1%, 38.5%, and 20.9% of samples from South Asia, Sub-Saharan Africa, and Southeast Asia, respectively, exceeded the maximum level for aflatoxin B1 (20 µg/kg). In several regions, mycotoxin concentrations in maize showed a pronounced year-to-year variation that could be explained by rainfall or temperature during sensitive periods of grain development. A large fraction of samples (64%) was co-contaminated with ≥ 2 mycotoxins. Most frequently observed mycotoxin mixtures were combinations of deoxynivalenol, zearalenone, and fumonisins, as well as fumonisins and aflatoxin B1. Deoxynivalenol and zearalenone concentrations were correlated in maize and wheat. In conclusion, according to an extensive global survey, mycotoxin (co-)contamination of animal feed is common, shows regional trends, and is governed in part by climate and weather.

ACS Style

Christiane Gruber-Dorninger; Timothy Jenkins; Gerd Schatzmayr. Global Mycotoxin Occurrence in Feed: A Ten-Year Survey. Toxins 2019, 11, 375 .

AMA Style

Christiane Gruber-Dorninger, Timothy Jenkins, Gerd Schatzmayr. Global Mycotoxin Occurrence in Feed: A Ten-Year Survey. Toxins. 2019; 11 (7):375.

Chicago/Turabian Style

Christiane Gruber-Dorninger; Timothy Jenkins; Gerd Schatzmayr. 2019. "Global Mycotoxin Occurrence in Feed: A Ten-Year Survey." Toxins 11, no. 7: 375.

Book chapter
Published: 23 November 2018 in Corn
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Corn is commonly contaminated with toxic secondary metabolites (mycotoxins) from fungi. Mycotoxins can impact the health of humans and animals consuming corn-based food and feeds. Economic losses associated with mycotoxins occur because of reduced crop yields, loss of crop value, effects on domestic animal productivity, and human health impacts. The most important mycotoxins in corn worldwide are aflatoxins, fumonisins, trichothecenes (especially deoxynivalenol), and zearalenone. These compounds are produced by fungal species in the fungal genera Aspergillus and Fusarium. Species of Penicillium also produce mycotoxins that can occur in corn. Mycotoxins are chemically diverse and capable of inducing a wide variety of acute and chronic symptoms, ranging from feed refusal to rapid death or cancer. Accurate detection and quantitation of mycotoxins is an essential component of the prevention, diagnosis, and remediation of mycotoxin-related problems in livestock and human food. Management of mycotoxin problems requires a multifaceted approach including preharvest and postharvest strategies for preventing mycotoxin development or mitigating the effects of mycotoxins. Technological advances in crop production methods and postharvest handling and treatment of corn continue to enhance the ability of corn producers and processors to diminish the likelihood of unsafe levels of mycotoxins.

ACS Style

Gary P. Munkvold; Silvina Arias; Ines Taschl; Christiane Gruber-Dorninger. Mycotoxins in Corn: Occurrence, Impacts, and Management. Corn 2018, 235 -287.

AMA Style

Gary P. Munkvold, Silvina Arias, Ines Taschl, Christiane Gruber-Dorninger. Mycotoxins in Corn: Occurrence, Impacts, and Management. Corn. 2018; ():235-287.

Chicago/Turabian Style

Gary P. Munkvold; Silvina Arias; Ines Taschl; Christiane Gruber-Dorninger. 2018. "Mycotoxins in Corn: Occurrence, Impacts, and Management." Corn , no. : 235-287.

Journal article
Published: 18 September 2018 in World Mycotoxin Journal
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As animal feed is prone to infestation with mycotoxin-producing fungi, mycotoxin contamination of feed should be monitored. Here, we report a multi-mycotoxin survey of feed samples from Africa. We determined the concentrations of aflatoxins, fumonisins, deoxynivalenol, T-2 toxin, zearalenone and ochratoxin A in 1,045 samples of finished feed and feed raw materials (maize, maize silage, other cereals, etc.) from South Africa and 318 samples from Algeria, Tunisia, Morocco, Senegal, Côte d’Ivoire, Nigeria, Ghana, Namibia, Uganda, Kenya, Tanzania, Zambia and Madagascar. We compared the measured mycotoxin concentrations to regulatory limits or guidance values that are in effect in the European Union and analysed the co-occurrence of these mycotoxins. To determine the occurrence of other fungal secondary metabolites, a subset of the samples was analysed using a multi-analyte liquid chromatography tandem mass spectrometry-based method for the simultaneous detection of over 700 fungal metabolites. We found that 33.3% of maize samples and 54.4% of finished feed samples from Senegal, Côte d’Ivoire, Nigeria, Ghana, Namibia, Uganda, Kenya and Tanzania exceeded the European regulatory limit of 20 ng/g aflatoxins. The Fusarium mycotoxins zearalenone, fumonisins and deoxynivalenol were prevalent in all commodities from all countries, but concentrations were in most cases below European guidance values. Concentrations of deoxynivalenol and zearalenone were correlated. Several other Fusarium metabolites occurred frequently (e.g. moniliformin, beauvericin, aurofusarin) or in high concentrations (e.g. aurofusarin, fusaproliferin). Furthermore, high levels of diplodiatoxin were occasionally detected in samples from South Africa and the Alternaria metabolite tenuazonic acid was prevalent and reached high concentrations. In conclusion, aflatoxins frequently occurred in African feed samples in potentially unsafe concentrations. While Fusarium mycotoxins mostly occurred in concentrations below European guidance values, a correlation between deoxynivalenol and zearalenone concentrations suggests that toxicological interactions of these compounds deserve attention. Several less investigated fungal secondary metabolites occurred frequently or reached high concentrations.

ACS Style

C. Gruber-Dorninger; T. Jenkins; G. Schatzmayr. Multi-mycotoxin screening of feed and feed raw materials from Africa. World Mycotoxin Journal 2018, 11, 369 -383.

AMA Style

C. Gruber-Dorninger, T. Jenkins, G. Schatzmayr. Multi-mycotoxin screening of feed and feed raw materials from Africa. World Mycotoxin Journal. 2018; 11 (3):369-383.

Chicago/Turabian Style

C. Gruber-Dorninger; T. Jenkins; G. Schatzmayr. 2018. "Multi-mycotoxin screening of feed and feed raw materials from Africa." World Mycotoxin Journal 11, no. 3: 369-383.

Journal article
Published: 25 April 2018 in World Mycotoxin Journal
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Fumonisins are among the most prevalent mycotoxins in feedstuffs. They disrupt the sphingolipid metabolism, thereby inducing a plethora of toxic effects in livestock. Supplementation with mycotoxin-degrading enzymes is a promising strategy for the detoxification of feedstuffs in the animals’ gastrointestinal tract. Here, we evaluated the suitability of the fumonisin esterase FumD as a feed additive (FUMzyme®) for the prevention of fumonisin toxicity in pigs by using a combination of different fumonisin biomarkers (sphinganine to sphingosine (Sa/So) ratio in serum and organs, concentrations of fumonisin B1 and hydrolysed derivatives in urine and faeces). In a pre-trial, we exposed pigs to 30 mg/kg fumonisins in feed and found the minimum effective dose of FUMzyme to be 15 U/kg. In a second trial we investigated the long-term efficacy of this minimum effective FUMzyme dose to counteract toxic effects elicited by 6 weeks of exposure to 2.5 mg/kg fumonisins in a diet containing naturally contaminated maize. Supplementation of feed with the minimum effective FUMzyme dose prevented an increase in the Sa/So ratio in serum and kidneys of fumonisin exposed pigs. The Sa/So ratio in serum proved to be the most reliable biomarker. The fumonisin pattern in faeces was less suitable as biomarker for assessing the efficacy of FUMzyme due to natural gastrointestinal hydrolysis of fumonisins. Analysis of urine samples provided additional information about gastrointestinal fumonisin hydrolysis before fumonisin absorption, but was analytically challenging because of low urinary fumonisin concentrations.

ACS Style

Heidi Schwartz-Zimmermann; D. Hartinger; B. Doupovec; C. Gruber-Dorninger; M. Aleschko; S. Schaumberger; V. Nagl; I. Hahn; F. Berthiller; D. Schatzmayr; W.D. Moll. Application of biomarker methods to investigate FUMzyme mediated gastrointestinal hydrolysis of fumonisins in pigs. World Mycotoxin Journal 2018, 11, 201 -214.

AMA Style

Heidi Schwartz-Zimmermann, D. Hartinger, B. Doupovec, C. Gruber-Dorninger, M. Aleschko, S. Schaumberger, V. Nagl, I. Hahn, F. Berthiller, D. Schatzmayr, W.D. Moll. Application of biomarker methods to investigate FUMzyme mediated gastrointestinal hydrolysis of fumonisins in pigs. World Mycotoxin Journal. 2018; 11 (2):201-214.

Chicago/Turabian Style

Heidi Schwartz-Zimmermann; D. Hartinger; B. Doupovec; C. Gruber-Dorninger; M. Aleschko; S. Schaumberger; V. Nagl; I. Hahn; F. Berthiller; D. Schatzmayr; W.D. Moll. 2018. "Application of biomarker methods to investigate FUMzyme mediated gastrointestinal hydrolysis of fumonisins in pigs." World Mycotoxin Journal 11, no. 2: 201-214.

Journal article
Published: 01 December 2017 in Poultry Science
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Fumonisins (FB) are among the most frequently detected mycotoxins in feedstuffs and finished feed, and recent data suggest that the functions of the gastrointestinal tract (GIT) in poultry species might be compromised at doses ranging from 10 to 20 mg/kg, close to field incidences and below the US and EU guidelines. Strategies are therefore necessary to reduce the exposure of poultry to FB. In the present study, we assessed the efficacy of fumonisin esterase FumD (EC 3.1.1.87, commercial name FUMzyme®) to cleave the tricarballylic acid side chains of FB, leading to the formation of non-toxic hydrolyzed fumonisins in the GIT of broiler chickens. Broiler chickens were fed for 14 d (7 to 21 d of age) 3 different diets (6 birds/cage, 6 cages/diet), i) control feed (negative control group), ii) feed contaminated with 10 mg FB/kg (FB group), and iii) feed contaminated with 10 mg FB/kg and supplemented with 100 units of FUMzyme®/kg (FB+FUMzyme® group). To determine the degree of reduction of FB in the GIT, 2 characteristics were analyzed. First, the sphinganine-to-sphingosine ratio in the serum and liver was determined as a biomarker of effect for exposure to FB. Second, the concentration of fumonisin B1 and its hydrolyzed forms was evaluated in the gizzard, the proximal and distal parts of the small intestine, and the excreta. Significantly reduced sphinganine-to-sphingosine ratios in the serum and liver of the FB+FUMzyme® group (serum: 0.15 ± 0.01; liver: 0.17 ± 0.01) compared to the FB group (serum: 0.20 ± 0.01; liver: 0.29 ± 0.03) proved that supplementation of broiler feed with FUMzyme® was effective in partially counteracting the toxic effect of dietary FB. Likewise, FB concentrations in digesta and excreta were significantly reduced in the FB+FUMzyme® group compared to the FB group (P < 0.05; up to 75%). FUMzyme® furthermore partially counteracted FB-induced up-regulation of cytokine gene expression (IL-8 and IL-10) in the jejunum. The FB group showed significantly higher gene expression of IL-8 and IL-10 compared to the negative control group (IL-8: fold change = 2.9 ± 1.1, P < 0.05; IL-10: fold change = 3.6 ± 1.4, P < 0.05), whereas IL-8 and IL-10 mRNA levels were not significantly different in the FB+FUMzyme®® group compared to the other 2 groups. In conclusion, FUMzyme® is suitable to detoxify FB in chickens and maintain gut functions.

ACS Style

B Grenier; Heidi Schwartz-Zimmermann; C Gruber-Dorninger; I Dohnal; M Aleschko; G Schatzmayr; Wulf-Dieter Moll; T J Applegate. Enzymatic hydrolysis of fumonisins in the gastrointestinal tract of broiler chickens. Poultry Science 2017, 96, 4342 -4351.

AMA Style

B Grenier, Heidi Schwartz-Zimmermann, C Gruber-Dorninger, I Dohnal, M Aleschko, G Schatzmayr, Wulf-Dieter Moll, T J Applegate. Enzymatic hydrolysis of fumonisins in the gastrointestinal tract of broiler chickens. Poultry Science. 2017; 96 (12):4342-4351.

Chicago/Turabian Style

B Grenier; Heidi Schwartz-Zimmermann; C Gruber-Dorninger; I Dohnal; M Aleschko; G Schatzmayr; Wulf-Dieter Moll; T J Applegate. 2017. "Enzymatic hydrolysis of fumonisins in the gastrointestinal tract of broiler chickens." Poultry Science 96, no. 12: 4342-4351.

Review article
Published: 16 September 2016 in Journal of Agricultural and Food Chemistry
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Modern analytical techniques can determine a multitude of fungal metabolites contaminating food and feed. In addition to known mycotoxins, for which maximum levels in food are enforced, also currently unregulated, so-called “emerging mycotoxins” were shown to occur frequently in agricultural products. The aim of this review is to critically discuss the relevance of selected emerging mycotoxins to food and feed safety. Acute and chronic toxicity as well as occurrence data are presented for enniatins, beauvericin, moniliformin, fusaproliferin, fusaric acid, culmorin, butenolide, sterigmatocystin, emodin, mycophenolic acid, alternariol, alternariol monomethyl ether, and tenuazonic acid. By far not all of the detected compounds are toxicologically relevant at their naturally occurring levels and are therefore of little or no health concern to consumers. Still, gaps in knowledge have been identified for several compounds. These gaps should be closed by the scientific community in the coming years to allow a proper risk assessment.

ACS Style

Christiane Gruber-Dorninger; Barbara Novak; Veronika Nagl; Franz Berthiller. Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants. Journal of Agricultural and Food Chemistry 2016, 65, 7052 -7070.

AMA Style

Christiane Gruber-Dorninger, Barbara Novak, Veronika Nagl, Franz Berthiller. Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants. Journal of Agricultural and Food Chemistry. 2016; 65 (33):7052-7070.

Chicago/Turabian Style

Christiane Gruber-Dorninger; Barbara Novak; Veronika Nagl; Franz Berthiller. 2016. "Emerging Mycotoxins: Beyond Traditionally Determined Food Contaminants." Journal of Agricultural and Food Chemistry 65, no. 33: 7052-7070.

Journal article
Published: 02 September 2014 in The ISME Journal
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Numerous past studies have shown members of the genus Nitrospira to be the predominant nitrite-oxidizing bacteria (NOB) in nitrifying wastewater treatment plants (WWTPs). Only recently, the novel NOB 'Candidatus Nitrotoga arctica' was identified in permafrost soil and a close relative was enriched from activated sludge. Still, little is known about diversity, distribution and functional importance of Nitrotoga in natural and engineered ecosystems. Here we developed Nitrotoga 16S rRNA-specific PCR primers and fluorescence in situ hybridization (FISH) probes, which were applied to screen activated sludge samples from 20 full-scale WWTPs. Nitrotoga-like bacteria were detected by PCR in 11 samples and reached abundances detectable by FISH in seven sludges. They coexisted with Nitrospira in most of these WWTPs, but constituted the only detectable NOB in two systems. Quantitative FISH revealed that Nitrotoga accounted for nearly 2% of the total bacterial community in one of these plants, a number comparable to Nitrospira abundances in other WWTPs. Spatial statistics revealed that Nitrotoga coaggregated with ammonia-oxidizing bacteria, strongly supporting a functional role in nitrite oxidation. This activity was confirmed by FISH in combination with microradiography, which revealed nitrite-dependent autotrophic carbon fixation by Nitrotoga in situ. Correlation of the presence or absence with WWTP operational parameters indicated low temperatures as a main factor supporting high Nitrotoga abundances, although in incubation experiments these NOB remained active over an unexpected range of temperatures, and also at different ambient nitrite concentrations. In conclusion, this study demonstrates that Nitrotoga can be functionally important nitrite oxidizers in WWTPs and can even represent the only known NOB in engineered systems.

ACS Style

Sebastian Lücker; Jasmin Schwarz; Christiane Gruber-Dorninger; Eva Spieck; Michael Wagner; Holger Daims. Nitrotoga-like bacteria are previously unrecognized key nitrite oxidizers in full-scale wastewater treatment plants. The ISME Journal 2014, 9, 708 -720.

AMA Style

Sebastian Lücker, Jasmin Schwarz, Christiane Gruber-Dorninger, Eva Spieck, Michael Wagner, Holger Daims. Nitrotoga-like bacteria are previously unrecognized key nitrite oxidizers in full-scale wastewater treatment plants. The ISME Journal. 2014; 9 (3):708-720.

Chicago/Turabian Style

Sebastian Lücker; Jasmin Schwarz; Christiane Gruber-Dorninger; Eva Spieck; Michael Wagner; Holger Daims. 2014. "Nitrotoga-like bacteria are previously unrecognized key nitrite oxidizers in full-scale wastewater treatment plants." The ISME Journal 9, no. 3: 708-720.

Report
Published: 28 August 2014 in Science
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The bacterial oxidation of nitrite to nitrate is a key process of the biogeochemical nitrogen cycle. Nitrite-oxidizing bacteria are considered a highly specialized functional group, which depends on the supply of nitrite from other microorganisms and whose distribution strictly correlates with nitrification in the environment and in wastewater treatment plants. On the basis of genomics, physiological experiments, and single-cell analyses, we show that Nitrospira moscoviensis, which represents a widely distributed lineage of nitrite-oxidizing bacteria, has the genetic inventory to utilize hydrogen (H2) as an alternative energy source for aerobic respiration and grows on H2 without nitrite. CO2 fixation occurred with H2 as the sole electron donor. Our results demonstrate a chemolithoautotrophic lifestyle of nitrite-oxidizing bacteria outside the nitrogen cycle, suggesting greater ecological flexibility than previously assumed.

ACS Style

Hanna Koch; Alexander Galushko; Mads Albertsen; Arno Schintlmeister; Christiane Gruber-Dorninger; Sebastian Lücker; Eric Pelletier; Denis Le Paslier; Eva Spieck; Andreas Richter; Per H. Nielsen; Michael Wagner; Holger Daims. Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation. Science 2014, 345, 1052 -1054.

AMA Style

Hanna Koch, Alexander Galushko, Mads Albertsen, Arno Schintlmeister, Christiane Gruber-Dorninger, Sebastian Lücker, Eric Pelletier, Denis Le Paslier, Eva Spieck, Andreas Richter, Per H. Nielsen, Michael Wagner, Holger Daims. Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation. Science. 2014; 345 (6200):1052-1054.

Chicago/Turabian Style

Hanna Koch; Alexander Galushko; Mads Albertsen; Arno Schintlmeister; Christiane Gruber-Dorninger; Sebastian Lücker; Eric Pelletier; Denis Le Paslier; Eva Spieck; Andreas Richter; Per H. Nielsen; Michael Wagner; Holger Daims. 2014. "Growth of nitrite-oxidizing bacteria by aerobic hydrogen oxidation." Science 345, no. 6200: 1052-1054.

Journal article
Published: 22 August 2014 in The ISME Journal
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Nitrospira are chemolithoautotrophic nitrite-oxidizing bacteria that catalyze the second step of nitrification in most oxic habitats and are important for excess nitrogen removal from sewage in wastewater treatment plants (WWTPs). To date, little is known about their diversity and ecological niche partitioning within complex communities. In this study, the fine-scale community structure and function of Nitrospira was analyzed in two full-scale WWTPs as model ecosystems. In Nitrospira-specific 16S rRNA clone libraries retrieved from each plant, closely related phylogenetic clusters (16S rRNA identities between clusters ranged from 95.8% to 99.6%) within Nitrospira lineages I and II were found. Newly designed probes for fluorescence in situ hybridization (FISH) allowed the specific detection of several of these clusters, whose coexistence in the WWTPs was shown for prolonged periods of several years. In situ ecophysiological analyses based on FISH, relative abundance and spatial arrangement quantification, as well as microautoradiography revealed functional differences of these Nitrospira clusters regarding the preferred nitrite concentration, the utilization of formate as substrate and the spatial coaggregation with ammonia-oxidizing bacteria as symbiotic partners. Amplicon pyrosequencing of the nxrB gene, which encodes subunit beta of nitrite oxidoreductase of Nitrospira, revealed in one of the WWTPs as many as 121 species-level nxrB operational taxonomic units with highly uneven relative abundances in the amplicon library. These results show a previously unrecognized high diversity of Nitrospira in engineered systems, which is at least partially linked to niche differentiation and may have important implications for process stability.

ACS Style

Christiane Gruber-Dorninger; Michael Pester; Katharina Kitzinger; Domenico Savio; Alexander Loy; Thomas Rattei; Michael Wagner; Holger Daims. Functionally relevant diversity of closely related Nitrospira in activated sludge. The ISME Journal 2014, 9, 643 -655.

AMA Style

Christiane Gruber-Dorninger, Michael Pester, Katharina Kitzinger, Domenico Savio, Alexander Loy, Thomas Rattei, Michael Wagner, Holger Daims. Functionally relevant diversity of closely related Nitrospira in activated sludge. The ISME Journal. 2014; 9 (3):643-655.

Chicago/Turabian Style

Christiane Gruber-Dorninger; Michael Pester; Katharina Kitzinger; Domenico Savio; Alexander Loy; Thomas Rattei; Michael Wagner; Holger Daims. 2014. "Functionally relevant diversity of closely related Nitrospira in activated sludge." The ISME Journal 9, no. 3: 643-655.

Evaluation study
Published: 21 December 2012 in Applied and Environmental Microbiology
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Many studies of molecular microbial ecology rely on the characterization of microbial communities by PCR amplification, cloning, sequencing, and phylogenetic analysis of genes encoding rRNAs or functional marker enzymes. However, if the established clone libraries are dominated by one or a few sequence types, the cloned diversity is difficult to analyze by random clone sequencing. Here we present a novel approach to deplete unwanted sequence types from complex nucleic acid mixtures prior to cloning and downstream analyses. It employs catalytically active oligonucleotides containing locked nucleic acids (LNAzymes) for the specific cleavage of selected RNA targets. When combined within vitrotranscription and reverse transcriptase PCR, this LNAzyme-based technique can be used with DNA or RNA extracts from microbial communities. The simultaneous application of more than one specific LNAzyme allows the concurrent depletion of different sequence types from the same nucleic acid preparation. This new method was evaluated with defined mixtures of cloned 16S rRNA genes and then used to identify accompanying bacteria in an enrichment culture dominated by the nitrite oxidizer “CandidatusNitrospira defluvii.”In silicoanalysis revealed that the majority of publicly deposited rRNA-targeted oligonucleotide probes may be used as specific LNAzymes with no or only minor sequence modifications. This efficient and cost-effective approach will greatly facilitate tasks such as the identification of microbial symbionts in nucleic acid preparations dominated by plastid or mitochondrial rRNA genes from eukaryotic hosts, the detection of contaminants in microbial cultures, and the analysis of rare organisms in microbial communities of highly uneven composition.

ACS Style

Jan Dolinšek; Christiane Dorninger; Ilias Lagkouvardos; Michael Wagner; Holger Daims. Depletion of Unwanted Nucleic Acid Templates by Selective Cleavage: LNAzymes, Catalytically Active Oligonucleotides Containing Locked Nucleic Acids, Open a New Window for Detecting Rare Microbial Community Members. Applied and Environmental Microbiology 2012, 79, 1534 -1544.

AMA Style

Jan Dolinšek, Christiane Dorninger, Ilias Lagkouvardos, Michael Wagner, Holger Daims. Depletion of Unwanted Nucleic Acid Templates by Selective Cleavage: LNAzymes, Catalytically Active Oligonucleotides Containing Locked Nucleic Acids, Open a New Window for Detecting Rare Microbial Community Members. Applied and Environmental Microbiology. 2012; 79 (5):1534-1544.

Chicago/Turabian Style

Jan Dolinšek; Christiane Dorninger; Ilias Lagkouvardos; Michael Wagner; Holger Daims. 2012. "Depletion of Unwanted Nucleic Acid Templates by Selective Cleavage: LNAzymes, Catalytically Active Oligonucleotides Containing Locked Nucleic Acids, Open a New Window for Detecting Rare Microbial Community Members." Applied and Environmental Microbiology 79, no. 5: 1534-1544.

Methods
Published: 01 February 2010 in Applied and Environmental Microbiology
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Fluorescence in situ hybridization (FISH) with singly labeled rRNA-targeted oligonucleotide probes is widely applied for direct identification of microbes in the environment or in clinical specimens. Here we show that a replacement of singly labeled oligonucleotide probes with 5′-, 3′-doubly labeled probes at least doubles FISH signal intensity without causing specificity problems. Furthermore, Cy3-doubly labeled probes strongly increase in situ accessibility of rRNA target sites and thus provide more flexibility for probe design.

ACS Style

Kilian Stoecker; Christiane Dorninger; Holger Daims; Michael Wagner. Double Labeling of Oligonucleotide Probes for Fluorescence In Situ Hybridization (DOPE-FISH) Improves Signal Intensity and Increases rRNA Accessibility. Applied and Environmental Microbiology 2010, 76, 922 -926.

AMA Style

Kilian Stoecker, Christiane Dorninger, Holger Daims, Michael Wagner. Double Labeling of Oligonucleotide Probes for Fluorescence In Situ Hybridization (DOPE-FISH) Improves Signal Intensity and Increases rRNA Accessibility. Applied and Environmental Microbiology. 2010; 76 (3):922-926.

Chicago/Turabian Style

Kilian Stoecker; Christiane Dorninger; Holger Daims; Michael Wagner. 2010. "Double Labeling of Oligonucleotide Probes for Fluorescence In Situ Hybridization (DOPE-FISH) Improves Signal Intensity and Increases rRNA Accessibility." Applied and Environmental Microbiology 76, no. 3: 922-926.

Journal article
Published: 01 August 2008 in Water Science and Technology
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Significant NH4-N balance deficits were found during the measurement campaigns for the data collection for dynamic simulation studies at five full-scale sequencing batch reactor (SBR) waste water treatment plants (WWTPs), as well as during subsequent calibrations at the investigated plants. Subsequent lab scale investigations showed high evidence for dynamic, cycle- specific NH4+ ad-/desorption to the activated flocs as one reason for this balance deficit. This specific dynamic was investigated at five full-scale SBR plants for the search of the general causing mechanisms. The general mechanism found was a NH4+ desorption from the activated flocs at the end of the nitrification phase with subsequent nitrification and a chemical NH4+ adsorption at the flocs in the course of the filling phases. This NH4+ ad-/desorption corresponds to an antiparallel K+ ad/-desorption. One reasonable full-scale application was investigated at three SBR plants, a controlled filling phase at the beginning of the sedimentation phase. The results indicate that this kind of filling event must be specifically hydraulic controlled and optimised in order to prevent too high waste water break through into the clear water phase, which will subsequently be discarded.

ACS Style

P. Schwitalla; A. Mennerich; U. Austermann-Haun; A. Müller; C. Dorninger; H. Daims; N. C. Holm; S. G. E. Rönner-Holm. NH4+ ad-/desorption in sequencing batch reactors: simulation, laboratory and full-scale studies. Water Science and Technology 2008, 58, 345 -350.

AMA Style

P. Schwitalla, A. Mennerich, U. Austermann-Haun, A. Müller, C. Dorninger, H. Daims, N. C. Holm, S. G. E. Rönner-Holm. NH4+ ad-/desorption in sequencing batch reactors: simulation, laboratory and full-scale studies. Water Science and Technology. 2008; 58 (2):345-350.

Chicago/Turabian Style

P. Schwitalla; A. Mennerich; U. Austermann-Haun; A. Müller; C. Dorninger; H. Daims; N. C. Holm; S. G. E. Rönner-Holm. 2008. "NH4+ ad-/desorption in sequencing batch reactors: simulation, laboratory and full-scale studies." Water Science and Technology 58, no. 2: 345-350.