Unravelling New Metabolic Pathways: Supramolecular Organization of Aerobic Bacteria Respiratory Chains

Author(s):  
Ana Melo ◽  
Emma Cirlos ◽  
Miguel Teixeira
2021 ◽  
Vol 8 ◽  
Author(s):  
Sylvain Durand ◽  
Maude Guillier

In oxygen (O2) limiting environments, numerous aerobic bacteria have the ability to shift from aerobic to anaerobic respiration to release energy. This process requires alternative electron acceptor to replace O2 such as nitrate (NO3–), which has the next best reduction potential after O2. Depending on the organism, nitrate respiration involves different enzymes to convert NO3– to ammonium (NH4+) or dinitrogen (N2). The expression of these enzymes is tightly controlled by transcription factors (TFs). More recently, bacterial small regulatory RNAs (sRNAs), which are important regulators of the rapid adaptation of microorganisms to extremely diverse environments, have also been shown to control the expression of genes encoding enzymes or TFs related to nitrate respiration. In turn, these TFs control the synthesis of multiple sRNAs. These results suggest that sRNAs play a central role in the control of these metabolic pathways. Here we review the complex interplay between the transcriptional and the post-transcriptional regulators to efficiently control the respiration on nitrate.


2004 ◽  
Vol 279 (25) ◽  
pp. 26453-26461 ◽  
Author(s):  
Frank Krause ◽  
Christian Q. Scheckhuber ◽  
Alexandra Werner ◽  
Sascha Rexroth ◽  
Nicole H. Reifschneider ◽  
...  

Author(s):  
U. Aebi ◽  
L.E. Buhle ◽  
W.E. Fowler

Many important supramolecular structures such as filaments, microtubules, virus capsids and certain membrane proteins and bacterial cell walls exist as ordered polymers or two-dimensional crystalline arrays in vivo. In several instances it has been possible to induce soluble proteins to form ordered polymers or two-dimensional crystalline arrays in vitro. In both cases a combination of electron microscopy of negatively stained specimens with analog or digital image processing techniques has proven extremely useful for elucidating the molecular and supramolecular organization of the constituent proteins. However from the reconstructed stain exclusion patterns it is often difficult to identify distinct stain excluding regions with specific protein subunits. To this end it has been demonstrated that in some cases this ambiguity can be resolved by a combination of stoichiometric labeling of the ordered structures with subunit-specific antibody fragments (e.g. Fab) and image processing of the electron micrographs recorded from labeled and unlabeled structures.


2010 ◽  
Author(s):  
Sohan Lal ◽  
Kolin Paul ◽  
James Gomes
Keyword(s):  

Planta Medica ◽  
2016 ◽  
Vol 81 (S 01) ◽  
pp. S1-S381
Author(s):  
E Vikeved ◽  
R Buonfiglio ◽  
T Kogej ◽  
A Backlund

1965 ◽  
Vol 49 (3) ◽  
pp. 427-435 ◽  
Author(s):  
K. D. Voigt ◽  
J. Tamm ◽  
U. Volkwein ◽  
H. Schedewie

ABSTRACT Pregnenolone-sulphate (400 mg) was perfused through isolated dog livers. The following steroids were isolated in the perfusate: pregnenolone, progesterone, dehydroepiandrosterone, androst-5-ene-diol and the two steroid conjugates, i. e. pregnenolone-sulphate and dehydroepiandrosterone-sulphate. Two »free« steroids and one steroid conjugate could not be characterized. A tentative scheme for the metabolic pathways of pregnenolone-sulphate is presented.


2020 ◽  
Vol 33 (2) ◽  
pp. 102-105
Author(s):  
Joanna Bialowska ◽  
Witold Bojar ◽  
Tomasz Zareba ◽  
Stefan Tyski ◽  
Barbara Tymczyna-Borowicz

AbstractCross-infection involves the transmission of microorganisms through secretions, bodily fluids and excreta, as well as undisinfected surfaces and medical equipment. In the dental office, diseases are transmitted via various routes, e.g. from patient to dentist or other member of dental team, from doctor or dental team member to patient, from patient to another patient, from dental office to community and from community to patient. The study was conducted to evaluate the effectiveness of infection control in dental practices based on the qualitative and quantitative assessment of microbiological contaminants detected on the surface of filling material packaging used in dental offices. The material for research were 9 packages containing dental materials during their use in 3 dental settings. The packages were placed in sterile flasks and rinsed to wash microorganisms from the surfaces. The washes were filtered through membrane filters and cultured under proper aerobic and anaerobic conditions, and at elevated CO2 concentration. Microbial growth on TIO and TSB media was observed. The contamination of most samples remained low as indicated by the growth from one to a maximum of five colonies on TSA. The contamination remained at the level of 10-50 CFU/package, i.e. <100 CFU/single package. The tests evaluating the contamination of dental package surfaces with aerobic bacteria confirmed high hygiene standards observed in dental offices from which the packages were brought.


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