scholarly journals Roles of Organohalide-Respiring Dehalococcoidia in Carbon Cycling

mSystems ◽  
2020 ◽  
Vol 5 (3) ◽  
Author(s):  
Yi Yang ◽  
Robert Sanford ◽  
Jun Yan ◽  
Gao Chen ◽  
Natalie L. Cápiro ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
Reductive Dechlorination ◽  
Broad Distribution ◽  
Environmental Distribution ◽  
Functional Attributes ◽  
Chlorinated Pollutants ◽  
Syntrophic Oxidation ◽  
Culture Independent ◽  
Natural Formation ◽  
Terrestrial Biomes

ABSTRACT The class Dehalococcoidia within the Chloroflexi phylum comprises the obligate organohalide-respiring genera Dehalococcoides, Dehalogenimonas, and “Candidatus Dehalobium.” Knowledge of the unique ecophysiology and biochemistry of Dehalococcoidia has been largely derived from studies with enrichment cultures and isolates from sites impacted with chlorinated pollutants; however, culture-independent surveys found Dehalococcoidia sequences in marine, freshwater, and terrestrial biomes considered to be pristine (i.e., not impacted with organohalogens of anthropogenic origin). The broad environmental distribution of Dehalococcoidia, as well as other organohalide-respiring bacteria, supports the concept of active halogen cycling and the natural formation of organohalogens in various ecosystems. Dechlorination reduces recalcitrance and renders organics susceptible to metabolic oxidation by diverse microbial taxa. During reductive dechlorination, hydrogenotrophic organohalide-respiring bacteria, in particular Dehalococcoidia, can consume hydrogen to low consumption threshold concentrations (<0.3 nM) and enable syntrophic oxidation processes. These functional attributes and the broad distribution imply that Dehalococcoidia play relevant roles in carbon cycling in anoxic ecosystems.

scholarly journals Development of an Environmental Functional Gene Microarray for Soil Microbial Communities

2010 ◽  
Vol 76 (21) ◽  
pp. 7161-7170 ◽  
Author(s):  
Ken C. McGrath ◽  
Rhiannon Mondav ◽  
Regina Sintrajaya ◽  
Bill Slattery ◽  
Susanne Schmidt ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Environmental Samples ◽  
Agricultural Soils ◽  
Soil Microbial Communities ◽  
Functional Gene ◽  
Gene Microarray ◽  
Independent Manner ◽  
Soil Microbial ◽  
Functional Attributes ◽  
Culture Independent

ABSTRACT Functional attributes of microbial communities are difficult to study, and most current techniques rely on DNA- and rRNA-based profiling of taxa and genes, including microarrays containing sequences of known microorganisms. To quantify gene expression in environmental samples in a culture-independent manner, we constructed an environmental functional gene microarray (E-FGA) consisting of 13,056 mRNA-enriched anonymous microbial clones from diverse microbial communities to profile microbial gene transcripts. A new normalization method using internal spot standards was devised to overcome spotting and hybridization bias, enabling direct comparisons of microarrays. To evaluate potential applications of this metatranscriptomic approach for studying microbes in environmental samples, we tested the E-FGA by profiling the microbial activity of agricultural soils with a low or high flux of N2O. A total of 109 genes displayed expression that differed significantly between soils with low and high N2O emissions. We conclude that mRNA-based approaches such as the one presented here may complement existing techniques for assessing functional attributes of microbial communities.

scholarly journals Phylum Gemmatimonadota and Its Role in the Environment

2022 ◽  
Vol 10 (1) ◽  
pp. 151
Author(s):  
Izabela Mujakić ◽  
Kasia Piwosz ◽  
Michal Koblížek
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Current Knowledge ◽  
Reaction Centers ◽  
Aquatic Environments ◽  
Environmental Distribution ◽  
Anoxygenic Photosynthesis ◽  
Bacterial Reaction Centers ◽  
Culture Independent ◽  
Bacterial Groups

Bacteria are an important part of every ecosystem that they inhabit on Earth. Environmental microbiologists usually focus on a few dominant bacterial groups, neglecting less abundant ones, which collectively make up most of the microbial diversity. One of such less-studied phyla is Gemmatimonadota. Currently, the phylum contains only six cultured species. However, data from culture-independent studies indicate that members of Gemmatimonadota are common in diverse habitats. They are abundant in soils, where they seem to be frequently associated with plants and the rhizosphere. Moreover, Gemmatimonadota were found in aquatic environments, such as freshwaters, wastewater treatment plants, biofilms, and sediments. An important discovery was the identification of purple bacterial reaction centers and anoxygenic photosynthesis in this phylum, genes for which were likely acquired via horizontal gene transfer. So far, the capacity for anoxygenic photosynthesis has been described for two cultured species: Gemmatimonas phototrophica and Gemmatimonas groenlandica. Moreover, analyses of metagenome-assembled genomes indicate that it is also common in uncultured lineages of Gemmatimonadota. This review summarizes the current knowledge about this understudied bacterial phylum with an emphasis on its environmental distribution.

scholarly journals Expanding the Known Diversity and Environmental Distribution of an Uncultured Phylogenetic Division of Bacteria

2000 ◽  
Vol 66 (4) ◽  
pp. 1617-1621 ◽  
Author(s):  
Michael A. Dojka ◽  
J. Kirk Harris ◽  
Norman R. Pace
Keyword(s):  
Sequence Difference ◽  
Environmental Distribution ◽  
Contaminated Aquifer ◽  
Phylogenetic Methods ◽  
Bacterial Division ◽  
Culture Independent ◽  
Molecular Phylogenetic ◽  
Candidate Division ◽  
Phylogenetic Divergence ◽  
Do So

ABSTRACT Culture-independent molecular phylogenetic methods were used to explore the breadth of diversity and environmental distribution of members of the division-level “candidate” phylogenetic group WS6, recently discovered in a contaminated aquifer and with no cultivated representatives. A broad diversity of WS6-affiliated sequences were cloned from 7 of 12 environments investigated: mainly from anaerobic sediment environments. The number of sequences representing the WS6 candidate division was increased from 3 to 60 in this study. The extent of phylogenetic divergence (sequence difference) in this candidate division was found to be among the largest of any known bacterial division. This indicates that organisms representing the WS6 phylogenetic division offer a broad diversity of undiscovered biochemical and metabolic novelty. These results provide a framework for the further study of these evidently important kinds of organisms and tools, the sequences, with which to do so.

Melatonin actions in the heart; more than a hormone

2018 ◽  
Vol 1 (1) ◽  
pp. 21-26 ◽  
Author(s):  
Darío Acuña-Castroviejo ◽  
Maria T Noguiera-Navarro ◽  
Russel J Reiter ◽  
Germaine Escames
Keyword(s):  
Cell Membranes ◽  
Myocardial Cell ◽  
Rat Tissues ◽  
Dependent Manner ◽  
Broad Distribution ◽  
Multiple Organs ◽  
High Doses ◽  
Extrapineal Melatonin ◽  
Dose Dependent ◽  
Different Doses

Due to the broad distribution of extrapineal melatonin in multiple organs and tissues, we analyzed the presence and subcellular distribution of the indoleamine in the heart of rats. Groups of sham-operated and pinealectomized rats were sacrificed at different times along the day, and the melatonin content in myocardial cell membranes, cytosol, nuclei and mitochondria, were measured. Other groups of control animals were treated with different doses of melatonin to monitor its intracellular distribution. The results show that melatonin levels in the cell membrane, cytosol, nucleus, and mitochondria vary along the day, without showing a circadian rhythm. Pinealectomized animals trend to show higher values than sham-operated rats. Exogenous administration of melatonin yields its accumulation in a dose-dependent manner in all subcellular compartments analyzed, with maximal concentrations found in cell membranes at doses of 200 mg/kg bw melatonin. Interestingly, at dose of 40 mg/kg b.w, maximal concentration of melatonin was reached in the nucleus and mitochondrion. The results confirm previous data in other rat tissues including liver and brain, and support that melatonin is not uniformly distributed in the cell, whereas high doses of melatonin may be required for therapeutic purposes.

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