scholarly journals Activity and electron donor preference of two denitrifying bacterial strains identified by Raman gas spectroscopy

2021 ◽  
Author(s):  
Annika Blohm ◽  
Swatantar Kumar ◽  
Andreas Knebl ◽  
Martina Herrmann ◽  
Kirsten Küsel ◽  
...  
Keyword(s):  
Electron Donor ◽  
Complex Analysis ◽  
Gas Analysis ◽  
Bacterial Strains ◽  
Raman Spectroscopic ◽  
Substrate Preferences ◽  
Exchange Processes ◽  
Donor Preference ◽  
Simultaneous Identification ◽  
Heterotrophic Denitrification

AbstractHuman activities have greatly increased the input of reactive nitrogen species into the environment and disturbed the balance of the global N cycle. This imbalance may be offset by bacterial denitrification, an important process in maintaining the ecological balance of nitrogen. However, our understanding of the activity of mixotrophic denitrifying bacteria is not complete, as most research has focused on heterotrophic denitrification. The aim of this study was to investigate substrate preferences for two mixotrophic denitrifying bacterial strains, Acidovorax delafieldii and Hydrogenophaga taeniospiralis, under heterotrophic, autotrophic or mixotrophic conditions. This complex analysis was achieved by simultaneous identification and quantification of H2, O2, CO2, 14N2, 15N2 and 15N2O in course of the denitrification process with help of cavity-enhanced Raman spectroscopic (CERS) multi-gas analysis. To disentangle electron donor preferences for both bacterial strains, microcosm-based incubation experiments under varying substrate conditions were conducted. We found that Acidovorax delafieldii preferentially performed heterotrophic denitrification in the mixotrophic sub-experiments, while Hydrogenophaga taeniospiralis preferred autotrophic denitrification in the mixotrophic incubation. These observations were supported by stoichiometric calculations. The results demonstrate the prowess of advanced Raman multi-gas analysis to study substrate use and electron donor preferences in denitrification, based on the comprehensive quantification of complex microbial gas exchange processes.

Research Tracker 6 Accelerometer Calibration and Validation in Comparison to GENEActiv, ActiGraph, and Gas Analysis in Young Adults

2019 ◽  
Vol 2 (3) ◽  
pp. 176-187
Author(s):  
Emma L. J. Eyre ◽  
Jason Tallis ◽  
Susie Wilson ◽  
Lee Wilde ◽  
Liam Akhurst ◽  
...  
Keyword(s):  
Physical Activity ◽  
Young Adults ◽  
Convergent Validity ◽  
Complex Analysis ◽  
Axial Vector ◽  
Gas Analysis ◽  
Moderate Activity ◽  
Sedentary Behaviors ◽  
Cut Points ◽  
Activity Intensity

Background: The ability to objectively assess physical activity and inactivity in free living individuals is important in understanding activity patterns and the dose response relationship with health. Currently, a large number of research tools exist, but little evidence has examined the validity/utility of the Research Tracker 6 (RT6) monitor. Questions remain in regard to the best placements, positions, and cut-points in young adults to determine activity intensity across a range of activities. This study sought to address this gap in young adults. The study aims were 1) to examine criterion validity of RT6 in comparison to breath-by-breath gas analysis; 2) convergent validity of RT6 in comparison to ActiGraph and GENEActiv; 3) development of RT6 tri-axial vector magnitude cut-points to classify physical activity at different intensities (i.e., for sedentary, moderate, and vigorous); 4) to compare the generated cut-points of the RT6 in comparison to other tools. Methods: Following ethics approval and informed consent, 31 young adults (age = 22±3 years: BMI = 23±3 kg/m2) undertook five modes of physical activity/sedentary behaviors while wearing three different accelerometers at hip and wrist locations (ActiGraph GT9X Link, GENEActiv, RT6). Expired gas was sampled during the five activities (MetaMax 3B). Correlational analysis assessed the relationship between accelerometer devices and METs/VO2. Receiver Operating Characteristic Curves analysis were used to calculate area under the curve and define cut-points for physical activity intensities. Results: The RT6 demonstrated criterion and convergent validity (r = 0.662–0.966, P < .05). RT6 generally performed good to excellent across activity intensities and monitor position (sedentary [AUC = 0.862–0.911], moderate [AUC = 0.849–0.830], vigorous [AUC = 0.872–0.877]) for non-dominant and dominant position, respectively. Cut-points were derived across activity intensities for non-dominant- and dominant-worn RT6 devices. Comparison of the RT6 derived cut-points identified appropriate agreement with comparative tools but yields the strongest agreement with the ActiGraph monitor at the hip location during sedentary, light, and moderate activity. Conclusion: The RT6 performed similar to the ActiGraph and GENEActiv and is capable of classifying the intensity of physical activity in young adults. As such this may offer a more useable tool for understanding current physical activity levels and in intervention studies to monitor and track changes without the excessive need for downloading and making complex analysis, especially given the option to view energy expenditure data while wearing it. The RT6 should be placed on the dominant hip when determining activities that are sedentary, moderate, or vigorous intensity.

scholarly journals Substrate preferences, phylogenetic and biochemical properties of proteolytic bacteria present in the digestive tract of Nile tilapia

2021 ◽  
Author(s):  
Tanim Jabid Hossain ◽  
Mukta Das ◽  
Ferdausi Ali ◽  
Sumaiya Islam Chowdhury ◽  
Subrina Akter Zedny
Keyword(s):  
Nile Tilapia ◽  
Molecular Taxonomy ◽  
Skim Milk ◽  
Biochemical Properties ◽  
Protease Production ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Substrate Preferences ◽  
Proteolytic Bacteria ◽  
Excellent Source

Abstract Vertebrate intestine appears an excellent source of proteolytic bacteria for industrial and probiotic use. We therefore aimed obtaining the gut-associated proteolytic species of Nile tilapia. We’ve isolated twenty six bacterial strains from its intestinal tract, seven of which showed exoprotease activity with the formation of clear halos on skim milk. Their depolymerization ability was further assessed on three distinct proteins including casein, gelatin and albumin. All the isolates could successfully hydrolyze the three substrates indicating relatively broad specificity of their secreted proteases. Molecular taxonomy and phylogeny of the proteolytic isolates were determined based on their 16S rRNA gene barcoding which suggested that the seven strains belong to three phyla viz. Firmicutes, Proteobacteria and Actinobacteria, distributed across the genera Priestia, Citrobacter, Pseudomonas, Stenotrophomonas, Burkholderia, Providencia and Micrococcus. The isolates were further characterized by a comprehensive study of their morphological, cultural, cellular and biochemical properties which were consistent with the phylogenetic annotations. To reveal their proteolytic capacity alongside substrate preferences, enzyme-production was determined by the diffusion assay. The Pseudomonas, Stenotrophomonas and Micrococcus isolates appeared most promising with maximum protease production on casein, gelatin and albumin media respectively. Our findings present valuable insights into the phylogenetic and biochemical properties of gut-associated proteolytic strains of Nile tilapia.

scholarly journals Substrate preferences, phylogenetic and biochemical properties of proteolytic bacteria present in the digestive tract of Nile tilapia (Oreochromis niloticus)

2021 ◽  
Vol 7 (4) ◽  
pp. 528-545
Author(s):  
Tanim Jabid Hossain ◽  
◽  
Mukta Das ◽  
Ferdausi Ali ◽  
Sumaiya Islam Chowdhury ◽  
...  
Keyword(s):  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Molecular Taxonomy ◽  
Skim Milk ◽  
Biochemical Properties ◽  
Protease Production ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Substrate Preferences ◽  
Proteolytic Bacteria

<abstract> <p>Vertebrate intestine appears to be an excellent source of proteolytic bacteria for industrial and probiotic use. We therefore aimed at obtaining the gut-associated proteolytic species of Nile tilapia (<italic>Oreochromis niloticus</italic>). We have isolated twenty six bacterial strains from its intestinal tract, seven of which showed exoprotease activity with the formation of clear halos on skim milk. Their depolymerization ability was further assessed on three distinct proteins including casein, gelatin, and albumin. All the isolates could successfully hydrolyze the three substrates indicating relatively broad specificity of their secreted proteases. Molecular taxonomy and phylogeny of the proteolytic isolates were determined based on their 16S rRNA gene barcoding, which suggested that the seven strains belong to three phyla viz. Firmicutes, Proteobacteria, and Actinobacteria, distributed across the genera <italic>Priestia</italic>, <italic>Citrobacter</italic>, <italic>Pseudomonas</italic>, <italic>Stenotrophomonas</italic>, <italic>Burkholderia</italic>, <italic>Providencia</italic>, and <italic>Micrococcus</italic>. The isolates were further characterized by a comprehensive study of their morphological, cultural, cellular and biochemical properties which were consistent with the phylogenetic annotations. To reveal their proteolytic capacity alongside substrate preferences, enzyme-production was determined by the diffusion assay. The <italic>Pseudomonas</italic>, <italic>Stenotrophomonas</italic> and <italic>Micrococcus</italic> isolates appeared to be most promising with maximum protease production on casein, gelatin, and albumin media respectively. Our findings present valuable insights into the phylogenetic and biochemical properties of gut-associated proteolytic strains of Nile tilapia.</p> </abstract>

Compared microbiology of granular sludge under autotrophic, mixotrophic and heterotrophic denitrification conditions

2009 ◽  
Vol 59 (6) ◽  
pp. 1227-1236 ◽  
Author(s):  
N. Fernández ◽  
R. Sierra-Alvarez ◽  
R. Amils ◽  
J. A. Field ◽  
J. L. Sanz
Keyword(s):  
Electron Donor ◽  
Water Contamination ◽  
Granular Sludge ◽  
Electron Donors ◽  
Thiobacillus Denitrificans ◽  
Microbial Biodiversity ◽  
Real Potential ◽  
Terminal Electron Acceptor ◽  
Uasb Reactors ◽  
Heterotrophic Denitrification

Water contamination by nitrate is a wideworld extended phenomena. Biological autotrophic denitrification has a real potential to face this problem and presents less drawbacks than the most extended heterotrophic denitrification. Three bench-scale UASB reactors were operated under autotrophic (R1, H2S as electron donor), mixotrophic (R2, H2S plus p-cresol as electron donors) and heterotrophic (R3, p-cresol as electron donor) conditions using nitrate as terminal electron acceptor. 16S rDNA genetic libraries were built up to compare their microbial biodiversity. Six different bacteria phyla and three archaeal classes were observed. Proteobacteria was the main phyla in all reactors standing out the presence of denitrifiers. Microorganisms similar to Thiobacillus denitrificans and Acidovorax sp. performed the autotrophic denitification. These OTUs were displaced by chemoheterotrophic denitrifiers, especially by Limnobacter-like and Ottowia-like OTUs. Other phyla were Bacteroidetes, Chloroflexi, Firmicutes and Actinobacteria that - as well as Archaea members - were implicated in the degradation of organic matter, as substrate added as coming from endogenous sludge decay under autotrophic conditions. Archaea diversity remained low in all the reactors being Methanosaeta concilii the most abundant one.

scholarly journals Metabolic mechanisms of nitrogen substrate utilisation in three rhizosphere bacterial strains investigated using quantitative proteomics

2019 ◽  
Author(s):  
Richard P. Jacoby ◽  
Antonella Succurro ◽  
Stanislav Kopriva
Keyword(s):  
Metabolic Network ◽  
Protein Level ◽  
Metabolic Pathways ◽  
Quantitative Proteomics ◽  
Molecular Mechanisms ◽  
Nitrogen Sources ◽  
Organic N ◽  
Bacterial Strains ◽  
Substrate Utilisation ◽  
Substrate Preferences

AbstractNitrogen metabolism in the rhizosphere microbiome plays an important role in mediating plant nutrition, particularly under low inputs of mineral fertilisers. However, there is relatively little mechanistic information about which genes and metabolic pathways are induced by rhizosphere bacterial strains to utilise diverse nitrogen substrates. Here we investigate nitrogen substrate utilisation in three taxonomically diverse bacterial strains previously isolated from Arabidopsis roots. The three strains represent taxa that are consistently detected as core members of the plant microbiome: Pseudomonas, Streptomyces and Rhizobium. We use phenotype microarrays to determine the nitrogen substrate preferences of these strains, and compare the experimental results versus computational simulations of genome-scale metabolic network models obtained with EnsembleFBA. Results show that all three strains exhibit generalistic nitrogen substrate preferences, with substrate utilisation being well predicted by EnsembleFBA. Using label-free quantitative proteomics, we document hundreds of proteins in each strain that exhibit differential abundance values following cultivation on five different nitrogen sources: ammonium, glutamate, lysine, serine and urea. Proteomic data show that the three strains use different metabolic strategies to utilise specific nitrogen sources. One diverging trait appears to be their degree of proteomic flexibility, withPseudomonassp.Root9utilising lysine nutrition via widespread protein-level alterations to its flexible metabolic network, whereasRhizobiumsp.Root491shows relatively stable proteome composition across diverse nitrogen sources. Our results give new protein-level information about the specific transporters and enzymes induced by diverse rhizosphere bacterial strains to utilise organic nitrogen substrates.ImportanceNitrogen is the primary macronutrient required for plant growth. In contemporary agriculture, the vast majority of nitrogen is delivered via mineral fertilisers, which have undesirable environmental consequences such as waterway eutrophication and greenhouse gas production. There is increasing research interest in designing agricultural systems that mimic natural ecosystems, where nitrogen compounds are cycled between plants and soil, with the mineralisation of recalcitrant soil organic-N molecules mediated via microbial metabolism. However, to date there is little mechanistic information about which genes and metabolic pathways are induced by rhizosphere bacterial strains to metabolise organic-N molecules. Here, we use quantitative proteomics to provide new information about the molecular mechanisms utilised by taxonomically diverse rhizosphere bacterial strains to utilise different nitrogen substrates. Furthermore, we generate computational models of bacterial metabolism from a minimal set of experimental information, providing a workflow that can be easily reused to predict nitrogen substrate utilisation in other strains.

scholarly journals Substrate preferences, phylogenetic and biochemical properties of proteolytic bacteria present in the digestive tract of Nile tilapia

2021 ◽  
Author(s):  
Tanim Jabid Hossain ◽  
Mukta Das ◽  
Ferdausi Ali ◽  
Sumaiya Islam Chowdhury ◽  
Subrina Akter Zedny
Keyword(s):  
Nile Tilapia ◽  
Molecular Taxonomy ◽  
Skim Milk ◽  
Biochemical Properties ◽  
Protease Production ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Substrate Preferences ◽  
Proteolytic Bacteria ◽  
Excellent Source

Vertebrate intestine appears an excellent source of proteolytic bacteria for industrial and probiotic use. We therefore aimed obtaining the gut-associated proteolytic species of Nile tilapia. We have isolated twenty six bacterial strains from its intestinal tract, seven of which showed exoprotease activity with the formation of clear halos on skim milk. Their depolymerization ability was further assessed on three distinct proteins including casein, gelatin and albumin. All the isolates could successfully hydrolyze the three substrates indicating relatively broad specificity of their secreted proteases. Molecular taxonomy and phylogeny of the proteolytic isolates were determined based on their 16S rRNA gene barcoding which suggested that the seven strains belong to three phyla viz. Firmicutes, Proteobacteria and Actinobacteria, distributed across the genera Priestia, Citrobacter, Pseudomonas, Stenotrophomonas, Burkholderia, Providencia and Micrococcus. The isolates were further characterized by a comprehensive study of their morphological, cultural, cellular and biochemical properties which were consistent with the phylogenetic annotations. To reveal their proteolytic capacity alongside substrate preferences, enzyme-production was determined by the diffusion assay. The Pseudomonas, Stenotrophomonas and Micrococcus isolates appeared most promising with maximum protease production on casein, gelatin and albumin media respectively. Our findings present valuable insights into the phylogenetic and biochemical properties of gut-associated proteolytic strains of Nile tilapia.

Social exchange processes, health behaviour, and health behaviour change

2008 ◽  
Vol 16 (3) ◽  
pp. 131-134
Author(s):  
Urte Scholz ◽  
Rainer Hornung
Keyword(s):  
Social Exchange ◽  
Health Behaviour ◽  
Psychological Research ◽  
Smoking Behaviour ◽  
Self Report ◽  
Long Term Effects ◽  
Main Research ◽  
Research Areas ◽  
Exchange Processes ◽  
Multi Method Approach

Abstract. The main research areas of the Social and Health Psychology group at the Department of Psychology at the University of Zurich, Switzerland, are introduced. Exemplarily, three currently ongoing projects are described. The project ”Dyadic exchange processes in couples facing dementia” examines social exchanges in couples with the husband suffering from dementia and is based on Equity Theory. This project applies a multi-method approach by combining self-report with observational data. The ”Swiss Tobacco Monitoring System” (TMS) is a representative survey on smoking behaviour in Switzerland. Besides its survey character, the Swiss TMS also allows for testing psychological research questions on smoking with a representative sample. The project, ”Theory-based planning interventions for changing nutrition behaviour in overweight individuals”, elaborates on the concept of planning. More specifically, it is tested whether there is a critical amount of repetitions of a planning intervention (e.g., three or nine times) in order to ensure long-term effects.

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