Incorporating Concentration-Dependent Sediment Microbial Activity into Methylmercury Production Kinetics Modeling

2021 ◽  
Author(s):  
Grace E. Schwartz ◽  
Katherine A Muller ◽  
Saubhagya S Rathore ◽  
Regina L Wilpiszeski ◽  
Alyssa A Carrell ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Microbial Activity ◽  
Inorganic Mercury ◽  
Anaerobic Microorganisms ◽  
Kinetics Modeling ◽  
Production Kinetics ◽  
Anoxic Environments ◽  
Kinetics Of ◽  
Methylmercury Production

In anoxic environments, anaerobic microorganisms carrying the hgcAB gene cluster can mediate the transformation of inorganic mercury (Hg(II)) to monomethylmercury (MMHg). The kinetics of Hg(II) transformation to MMHg in periphyton...

scholarly journals Widespread microbial mercury methylation genes in the global ocean

2019 ◽  
Author(s):  
Emilie Villar ◽  
Lea Cabrol ◽  
Lars-Eric Heimbürger-Boavida
Keyword(s):  
Ecosystem Health ◽  
Inorganic Mercury ◽  
Global Ocean ◽  
Anaerobic Microorganisms ◽  
Antarctic Sea Ice ◽  
Anoxic Environments ◽  
Nitrite Oxidizing Bacteria ◽  
Subsurface Waters ◽  
High Concentrations ◽  
Methylmercury Production

AbstractMethylmercury is a neurotoxin that bioaccumulates from seawater to high concentrations in marine fish, putting human and ecosystem health at risk. High methylmercury levels have been found in the oxic subsurface waters of all oceans, yet only anaerobic microorganisms have been identified so far as efficient methylmercury producers in anoxic environments. The microaerophilic nitrite oxidizing bacteriaNitrospinahas been previously suggested as a possible mercury methylator in Antarctic sea ice. However, the microorganisms processing inorganic mercury into methylmercury in oxic seawater remain unknown. Here we show metagenomic evidence from open ocean for widespread microbial methylmercury production in oxic subsurface waters. We find high abundances of the key mercury methylating geneshgcABacross all oceans corresponding to taxonomic relatives of known mercury methylators from Deltaproteobacteria, Firmicutes and Chloroflexi. Our results identifyNitrospinaas the predominant and widespread key player for methylmercury production in the oxic subsurface waters of the global ocean.

Investigations on the production kinetics of ionic alkali–rare gas excimers

1992 ◽  
Vol 97 (5) ◽  
pp. 3325-3332 ◽  
Author(s):  
M. Mantel ◽  
M. Schumann ◽  
A. Giez ◽  
H. Langhoff ◽  
W. Hammer ◽  
...  
Keyword(s):  
Rare Gas ◽  
Production Kinetics ◽  
Kinetics Of

Growth and production kinetics of human × mouse and mouse hybridoma cells at reduced temperature and serum content

1992 ◽  
Vol 25 (3) ◽  
pp. 319-331 ◽  
Author(s):  
Nicole Borth ◽  
Renate Heider ◽  
Ali Assadian ◽  
Hermann Katinger
Keyword(s):  
Hybridoma Cells ◽  
Production Kinetics ◽  
Kinetics Of ◽  
Reduced Temperature

scholarly journals Expanded Phylogenetic Diversity and Metabolic Flexibility of Mercury-Methylating Microorganisms

mSystems ◽  
2020 ◽  
Vol 5 (4) ◽  
Author(s):  
Elizabeth A. McDaniel ◽  
Benjamin D. Peterson ◽  
Sarah L. R. Stevens ◽  
Patricia Q. Tran ◽  
Karthik Anantharaman ◽  
...  
Keyword(s):  
Phylogenetic Diversity ◽  
Large Scale ◽  
Carbon Fixation ◽  
Anaerobic Bacteria ◽  
Inorganic Mercury ◽  
Metal Resistance ◽  
Metabolic Flexibility ◽  
Metabolic Diversity ◽  
Content Type ◽  
Methylmercury Production

ABSTRACT Methylmercury is a potent bioaccumulating neurotoxin that is produced by specific microorganisms that methylate inorganic mercury. Methylmercury production in diverse anaerobic bacteria and archaea was recently linked to the hgcAB genes. However, the full phylogenetic and metabolic diversity of mercury-methylating microorganisms has not been fully unraveled due to the limited number of cultured experimentally verified methylators and the limitations of primer-based molecular methods. Here, we describe the phylogenetic diversity and metabolic flexibility of putative mercury-methylating microorganisms by hgcAB identification in publicly available isolate genomes and metagenome-assembled genomes (MAGs) as well as novel freshwater MAGs. We demonstrate that putative mercury methylators are much more phylogenetically diverse than previously known and that hgcAB distribution among genomes is most likely due to several independent horizontal gene transfer events. The microorganisms we identified possess diverse metabolic capabilities spanning carbon fixation, sulfate reduction, nitrogen fixation, and metal resistance pathways. We identified 111 putative mercury methylators in a set of previously published permafrost metatranscriptomes and demonstrated that different methylating taxa may contribute to hgcA expression at different depths. Overall, we provide a framework for illuminating the microbial basis of mercury methylation using genome-resolved metagenomics and metatranscriptomics to identify putative methylators based upon hgcAB presence and describe their putative functions in the environment. IMPORTANCE Accurately assessing the production of bioaccumulative neurotoxic methylmercury by characterizing the phylogenetic diversity, metabolic functions, and activity of methylators in the environment is crucial for understanding constraints on the mercury cycle. Much of our understanding of methylmercury production is based on cultured anaerobic microorganisms within the Deltaproteobacteria, Firmicutes, and Euryarchaeota. Advances in next-generation sequencing technologies have enabled large-scale cultivation-independent surveys of diverse and poorly characterized microorganisms from numerous ecosystems. We used genome-resolved metagenomics and metatranscriptomics to highlight the vast phylogenetic and metabolic diversity of putative mercury methylators and their depth-discrete activities in thawing permafrost. This work underscores the importance of using genome-resolved metagenomics to survey specific putative methylating populations of a given mercury-impacted ecosystem.

A comparison of the suitability of different models for describing the gas production kinetics of whole-crop wheat

1998 ◽  
Vol 22 ◽  
pp. 215-216
Author(s):  
A. T. Adesogan ◽  
E. Owen ◽  
D. I. Givens
Keyword(s):  
Mathematical Model ◽  
Time Course ◽  
Rumen Fluid ◽  
Gas Production ◽  
Ruminal Fermentation ◽  
Production Kinetics ◽  
Fermentation Profile ◽  
Kinetics Of

Menkeet al. (1979), Beuvinket al. (1992) and Theodorouet al. (1994) developed techniques for measuring the time course of gas production of foods fermentedin vitrowith rumen fluid. These techniques require description of the fermentation profile with an appropriate mathematical model. Although several authors have used these techniques to study the ruminal fermentation of foods, little information is available on the suitability of the model chosen for describing the fermentation profile of the food under study. In this study, the models of Ørskov and McDonald (1979), Franceet al. (1993) and Beuvink and Kogut (1993) were fitted to thein vitrogas production profiles of 10 whole-crop wheat (WCW) forages (cv.Slepjner) to determine the model most suited to describing the data.

Methane production kinetics of pretreated slaughterhouse wastewater

2019 ◽  
Vol 130 ◽  
pp. 105385 ◽  
Author(s):  
Vianka Celina Hernández-Fydrych ◽  
Guillermo Benítez-Olivares ◽  
Mónica A. Meraz-Rodríguez ◽  
Mónica L. Salazar-Peláez ◽  
M. Carmen Fajardo-Ortiz
Keyword(s):  
Methane Production ◽  
Slaughterhouse Wastewater ◽  
Production Kinetics ◽  
Kinetics Of
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