Biochemical and regulatory properties of a respiratory island encoded by a conjugative plasmid in the extreme thermophile Thermus thermophilus

2006 ◽  
Vol 34 (1) ◽  
pp. 97-100 ◽  
Author(s):  
F. Cava ◽  
J. Berenguer
Keyword(s):  
Nadh Dehydrogenase ◽  
Current Knowledge ◽  
Thermus Thermophilus ◽  
Thermophilic Bacterium ◽  
Conjugative Plasmid ◽  
Nitrate Respiration ◽  
Final Electron ◽  
New Type ◽  
Regulatory Properties ◽  
Final Electron Acceptor

In the present paper, we summarize the current knowledge on the first step of the denitrification pathway in the ancestral extreme thermophilic bacterium Thermus thermophilus. In this organism, nitrate respiration is performed by a mobilizable respiratory island that encodes a new type of respiratory NADH dehydrogenase as electron donor, a tetrameric membrane nitrate reductase as final electron acceptor, two nitrate/nitrite transporters and the transcription factors required for their expression in response to nitrate and anoxia.

scholarly journals Nitrate Respiration in Thermus thermophilus NAR1: from Horizontal Gene Transfer to Internal Evolution

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1308
Author(s):  
Mercedes Sánchez-Costa ◽  
Alba Blesa ◽  
José Berenguer
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Nadh Dehydrogenase ◽  
Thermus Thermophilus ◽  
Nitrate Respiration ◽  
Small Plasmid ◽  
Nitrite Reductases ◽  
Nitrite Respiration ◽  
Nitrate And Nitrite ◽  
Internal Evolution

Genes coding for enzymes of the denitrification pathway appear randomly distributed among isolates of the ancestral genus Thermus, but only in few strains of the species Thermus thermophilus has the pathway been studied to a certain detail. Here, we review the enzymes involved in this pathway present in T. thermophilus NAR1, a strain extensively employed as a model for nitrate respiration, in the light of its full sequence recently assembled through a combination of PacBio and Illumina technologies in order to counteract the systematic errors introduced by the former technique. The genome of this strain is divided in four replicons, a chromosome of 2,021,843 bp, two megaplasmids of 370,865 and 77,135 bp and a small plasmid of 9799 pb. Nitrate respiration is encoded in the largest megaplasmid, pTTHNP4, within a region that includes operons for O2 and nitrate sensory systems, a nitrate reductase, nitrate and nitrite transporters and a nitrate specific NADH dehydrogenase, in addition to multiple insertion sequences (IS), suggesting its mobility-prone nature. Despite nitrite is the final product of nitrate respiration in this strain, the megaplasmid encodes two putative nitrite reductases of the cd1 and Cu-containing types, apparently inactivated by IS. No nitric oxide reductase genes have been found within this region, although the NorR sensory gene, needed for its expression, is found near the inactive nitrite respiration system. These data clearly support that partial denitrification in this strain is the consequence of recent deletions and IS insertions in genes involved in nitrite respiration. Based on these data, the capability of this strain to transfer or acquire denitrification clusters by horizontal gene transfer is discussed.

scholarly journals Nitrate Respiration in Thermus Thermophilus NAR1: From Horizontal Gene Transfer to Internal Evolution

2020 ◽  
Author(s):  
Mercedes Sánchez-Costa ◽  
Alba Blesa ◽  
José Berenguer
Keyword(s):  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Nadh Dehydrogenase ◽  
Thermus Thermophilus ◽  
Nitrate Respiration ◽  
Small Plasmid ◽  
Nitrite Reductases ◽  
Nitrite Respiration ◽  
Nitrate And Nitrite ◽  
Internal Evolution

Genes coding for enzymes of the denitrification pathway appear randomly distributed among isolates of the ancestral genus Thermus, but only in few strains of the species T. thermophilus the pathway has been studied to a certain detail. Here, we review the enzymes involved in this pathway present in T. thermophilus NAR1, a strain extensively employed as a model for nitrate respiration, on the light of its full sequence recently assembled through a combination of PacBio and Illumina technologies in order to counteract the systematic errors introduced by the former technique. The genome of this strain is divided in four replicons, a chromosome of 2,021,843 pb, two megaplasmids of 370,865 and 77,135 bp and a small plasmid of 9,799 pb. Nitrate respiration is encoded in the largest megaplasmid, pTTHNP4, within a region that includes operons for O2 and nitrate sensory systems, a nitrate reductase, nitrate and nitrite transporters and a nitrate specific NADH dehydrogenase, in addition to multiple insertion sequences (IS), suggesting its mobility-prone nature. Despite nitrite is the final product of nitrate respiration in this strain, the megaplasmid encodes two putative nitrite reductases of the cd1 and Cu-containing types, apparently inactivated by IS. No nitric oxide reductase genes have been found within this region, although the NorR sensory gene, needed for its expression, is found near the inactive nitrite respiration system. These data clearly support that partial denitrification in this strain is the consequence of recent deletions and IS insertions in genes involved in nitrite respiration. Based on these data, the capability of this strain to transfer or acquire denitrification clusters by horizontal gene transfer is discussed.

scholarly journals A New Type of NADH Dehydrogenase Specific for Nitrate Respiration in the Extreme ThermophileThermus thermophilus

2004 ◽  
Vol 279 (44) ◽  
pp. 45369-45378 ◽  
Author(s):  
Felipe Cava ◽  
Olga Zafra ◽  
Axel Magalon ◽  
Francis Blasco ◽  
J. Berenguer
Keyword(s):  
Type Strain ◽  
Wild Type Strain ◽  
Thermus Thermophilus ◽  
Data Bank ◽  
Nitrate Respiration ◽  
Wild Type ◽  
Quinone Oxidoreductase ◽  
C Terminus ◽  
New Type ◽  
Insertion Mutants

A four-gene operon (nrcDEFN) was identified within a conjugative element that allowsThermus thermophilusto use nitrate as an electron acceptor. Three of them encode homologues to components of bacterial respiratory chains: NrcD to ferredoxins; NrcF to iron-sulfur-containing subunits of succinate-quinone oxidoreductase (SQR); and NrcN to type-II NADH dehydrogenases (NDHs). The fourth gene,nrcE,encodes a membrane protein with no homologues in the protein data bank. Nitrate reduction with NADH was catalyzed by membrane fractions of the wild type strain, but was severely impaired innrc::katinsertion mutants. A fusion to a thermophilic reporter gene was used for the first time inThermusspp. to show that expression ofnrcrequired the presence of nitrate and anoxic conditions. Therefore, a role for thenrcproducts as a new type of membrane NDH specific for nitrate respiration was deduced. Consistent with this,nrc::katmutants grew more slowly than the wild type strain under anaerobic conditions, but not in the presence of oxygen. The oligomeric structure of this Nrc-NDH was deduced from the analysis of insertion mutants and a two-hybrid bacterial system. Attachment to the membrane of NrcD, NrcF, and NrcN was dependent on NrcE, whose cytoplasmic C terminus interacts with the three proteins. Interactions were also detected between NrcN and NrcF. Inactivation ofnrcFproduced solubilization of NrcN, but not of NrcD. These data lead us to conclude that the Nrc proteins form a distinct third type of bacterial respiratory NDH.

Functional anatomy of carnivorous traps

2018 ◽  
Author(s):  
Bartosz J. Płachno ◽  
Lyudmila E. Muravnik
Keyword(s):  
Current Knowledge ◽  
Functional Anatomy ◽  
Carnivorous Plant ◽  
Carnivorous Plants ◽  
New Type ◽  
Functional Units

We review the current knowledge of trap anatomy of carnivorous plants, with a focus on the diversity and structure of the glands that are used to attract, capture, kill and digest their prey and finally to absorb nutrients from carcasses of prey. These glands have diverse forms. Regardless of their structure and origin, they have the same functional units, but there are differences in subcellular mechanisms and adaptations for carnivory. We propose a new type of carnivorous plant trap—a ‘fecal traps—which has unique physiology, morphology, and anatomy for attracting the animals that are the source of excrement and also to retain and use it.

scholarly journals Characterization of DNA transport in the thermophilic bacterium Thermus thermophilus HB27

FEBS Journal ◽  
2006 ◽  
Vol 273 (18) ◽  
pp. 4210-4218 ◽  
Author(s):  
Cornelia Schwarzenlander ◽  
Beate Averhoff
Keyword(s):  
Thermus Thermophilus ◽  
Thermophilic Bacterium ◽  
Dna Transport

scholarly journals Glutamate Dehydrogenase from Thermus thermophilus Is Activated by AMP and Leucine as a Complex with Catalytically Inactive Adenine Phosphoribosyltransferase Homolog

2019 ◽  
Vol 201 (14) ◽  
Author(s):  
Takeo Tomita ◽  
Hajime Matsushita ◽  
Ayako Yoshida ◽  
Saori Kosono ◽  
Minoru Yoshida ◽  
...  
Keyword(s):  
Enzymatic Activity ◽  
Glutamate Dehydrogenase ◽  
Ternary Complex ◽  
Thermus Thermophilus ◽  
Thermophilic Bacterium ◽  
Regulatory Subunit ◽  
Binary Complex ◽  
Bacterial Cells ◽  
Adenine Phosphoribosyltransferase ◽  
Content Type

ABSTRACT Glutamate dehydrogenase (GDH) from a thermophilic bacterium, Thermus thermophilus, is composed of two heterologous subunits, GdhA and GdhB. In the heterocomplex, GdhB acts as the catalytic subunit, whereas GdhA lacks enzymatic activity and acts as the regulatory subunit for activation by leucine. In the present study, we performed a pulldown assay using recombinant T. thermophilus, producing GdhA fused with a His tag at the N terminus, and found that TTC1249 (APRTh), which is annotated as adenine phosphoribosyltransferase but lacks the enzymatic activity, was copurified with GdhA. When GdhA, GdhB, and APRTh were coproduced in Escherichia coli cells, they were purified as a ternary complex. The ternary complex exhibited GDH activity that was activated by leucine, as observed for the GdhA-GdhB binary complex. Furthermore, AMP activated GDH activity of the ternary complex, whereas such activation was not observed for the GdhA-GdhB binary complex. This suggests that APRTh mediates the allosteric activation of GDH by AMP. The present study demonstrates the presence of complicated regulatory mechanisms of GDH mediated by multiple compounds to control the carbon-nitrogen balance in bacterial cells. IMPORTANCE GDH, which catalyzes the synthesis and degradation of glutamate using NAD(P)(H), is a widely distributed enzyme among all domains of life. Mammalian GDH is regulated allosterically by multiple metabolites, in which the antenna helix plays a key role to transmit the allosteric signals. In contrast, bacterial GDH was believed not to be regulated allosterically because it lacks the antenna helix. We previously reported that GDH from Thermus thermophilus (TtGDH), which is composed of two heterologous subunits, is activated by leucine. In the present study, we found that AMP activates TtGDH using a catalytically inactive APRTh as the sensory subunit. This suggests that T. thermophilus possesses a complicated regulatory mechanism of GDH to control carbon and nitrogen metabolism.

Reduction of selenate and selenite to elemental selenium by Wolinella succinogenes

1992 ◽  
Vol 38 (12) ◽  
pp. 1328-1333 ◽  
Author(s):  
Francisco A. Tomei ◽  
Larry L. Barton ◽  
Cheryl L. Lemanski ◽  
Thomas G. Zocco
Keyword(s):  
Stationary Growth Phase ◽  
Elemental Selenium ◽  
Bacterial Cells ◽  
Wolinella Succinogenes ◽  
Stationary Growth ◽  
X Ray ◽  
Dense Granules ◽  
Transmission Electron ◽  
Final Electron ◽  
Final Electron Acceptor

Cultures of Wolinella succinogenes were adapted to grow in the presence of 1 mM [Formula: see text] or 10 mM [Formula: see text]. Both selenium salts were reduced to red, amorphous, elemental selenium but only after the culture reached the stationary growth phase. Bacterial cells taken from a culture actively reducing selenium were examined by transmission electron microscopy and were found to have large, electron-dense granules in the cytoplasm. These granules were verified by energy-dispersive X-ray spectroscopy to consist of selenium. Wolinella succinogenes was unable to grow with [Formula: see text] or [Formula: see text] as the final electron acceptor. Key words: Wolinella, selenium, cytology, selenate.

A new water-soluble bacterial NADH: fumarate oxidoreductase

2020 ◽  
Vol 367 (20) ◽  
Author(s):  
Yulia V Bertsova ◽  
Ilya P Oleynikov ◽  
Alexander V Bogachev
Keyword(s):  
Nadh Dehydrogenase ◽  
Reductase Activity ◽  
Domain Architecture ◽  
Water Soluble ◽  
Fumarate Reductase ◽  
Anaerobic Conditions ◽  
New Type ◽  
Prosthetic Groups ◽  
Low Rate ◽  
Covalently Bound

ABSTRACT The cytoplasmic fumarate reductase of Klebsiella pneumoniae (FRD) is a monomeric protein which contains three prosthetic groups: noncovalently bound FMN and FAD plus a covalently bound FMN. In the present work, NADH is revealed to be an inherent electron donor for this enzyme. We found that the fumarate reductase activity of FRD significantly exceeds its NADH dehydrogenase activity. During the catalysis of NADH:fumarate oxidoreductase reaction, FRD turnover is limited by a very low rate (∼10/s) of electron transfer between the noncovalently and covalently bound FMN moieties. Induction of FRD synthesis in K. pneumoniae cells was observed only under anaerobic conditions in the presence of fumarate or malate. Enzymes with the FRD-like domain architecture are widely distributed among various bacteria and apparently comprise a new type of water-soluble NADH:fumarate oxidoreductases.

scholarly journals HISTOCHEMICAL DEMONSTRATION OF 3α-HYDROXYSTEROID DEHYDROGENASE ACTIVITY

1966 ◽  
Vol 14 (1) ◽  
pp. 77-83 ◽  
Author(s):  
KÁROLY BALOGH
Keyword(s):  
Leydig Cells ◽  
Hydroxysteroid Dehydrogenase ◽  
Histochemical Demonstration ◽  
Female Rats ◽  
Ventral Prostate ◽  
Tetrazolium Salt ◽  
Rat Tissues ◽  
Final Electron ◽  
Nucleotide Specificity ◽  
Final Electron Acceptor

The reversible oxidation of 3α-hydroxysteroids to their corresponding 3-keto forms comprises an important step in the metabolism of C19-steroids. The described techniquue demonstrates the activity of the enzyme catalyzing this reaction, with the use of androsterone as a substrate and a tetrazolium salt as the final electron acceptor. The enzyme is specific for 3α-hydroxysteroids; there was no histochemical reaction with epiandrosterone, the β isomer of androsterone. Since 3α-hydroxysteroid dehydrogenase is soluble in aqueous solutions, it was necessary to increase the osmolarity of the incubation medium by adding polyvinylpyrrolidone in a final concentration of 20%. Although the enzyme has a dual nucleotide specificity, no appreciable differences were seen in its distribution pattern in rat tissues with either NAD or NADP as a coenzyme. In adult female rats, enzyme activity was present in the liver, kidneys and clitoral glands. In mature males, diformazan deposits were observed in the liver, kidneys, preputiai glands, epididymis, ventral prostate and Leydig cells.

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