Search results for "Anaerobic Bacteria"

Direct identification of microorganisms from thioglycolate broth by MALDI-TOF MS.

2017

We developed an easy MALDI-TOF MS-based assay to identify microorganisms directly from thioglycolate broth. A total of 101 positive thioglycolate broths inoculated with 15 different kinds of samples were evaluated. In 91 samples (90.1%), direct MALDI-TOF MS identifications were the same as those obtained after conventional laboratory procedures including subcultures. In 10 samples misidentified by direct processing, yeasts or mixed cultures grew in the thioglycolate subcultures, or high cellular debris hampered a correct analysis. This rapid method can provide a fast, clinically- relevant species-level identification without disturbing the daily workflow in clinical microbiology laboratorie…

Validation of a novel automatic deposition of bacteria and yeasts on MALDI target for MALDI-TOF MS-based identification using MALDI Colonyst robot

2017

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) -based identification of bacteria and fungi significantly changed the diagnostic process in clinical microbiology. We describe here a novel technique for bacterial and yeast deposition on MALDI target using an automated workflow resulting in an increase of the microbes' score of MALDI identification. We also provide a comparison of four different sample preparation methods. In the first step of the study, 100 Gram-negative bacteria, 100 Gram-positive bacteria, 20 anaerobic bacteria and 20 yeasts were spotted on the MALDI target using manual deposition, semi-extraction, wet deposition onto 70% formic …

Energy Transduction in Anaerobic Bacteria

2013

Anaerobic or facultatively anaerobic bacteria are able to grow in the absence of molecular oxygen by fermentation, anaerobic respiration, anoxygenic photosynthesis, and some other membrane-dependent reactions. Fermentation uses substrate-level phosphorylation for adenosine diphosphate phosphorylation, whereas the other processes rely on the formation of a H + or Na + potential over the membrane and a membrane-potential-driven ATP synthase. In growth reactions providing only a small free energy change, the latter reactions and use of a membrane potential is the preferred mechanism for energy conservation. Fermentation reactions supply products of biotechnological interest like short chain fa…

Transcriptional regulation and energetics of alternative respiratory pathways in facultatively anaerobic bacteria

1998

Abstract The facultatively anaerobic Escherichia coli is able to grow by aerobic and by anaerobic respiration. Despite the large difference in the amount of free energy that could maximally be conserved from aerobic versus anaerobic respiration, the proton potential and Δg ′ Phos are similar under both conditions. O 2 represses anaerobic respiration, and nitrate represses fumarate respiration. By this the terminal reductases of aerobic and anaerobic respiration are expressed in a way to obtain maximal H + e − ratios and ATP yields. The respiratory dehydrogenases, on the other hand, are not synthesized in a way to achieve maximal H + e − ratios. Most of the dehydrogenases of aerobic respirat…

Vibrio palustris sp. nov. and Vibrio spartinae sp. nov., two novel members of the Gazogenes clade, isolated from salt-marsh plants (Arthrocnemum macr…

2017

Two bacterial strains, EAod9T and SMJ21T, isolated from salt-marsh plants, were determined to be related to species of the genus Vibrio from from 16S rRNA sequence comparisons. Their closest phylogenetic relatives are members of the Gazogenes clade, Vibrio mangrovi and Vibrio rhizosphaerae , which show the greatest similarity to the SMJ21TrRNA sequence (97.3 and 97.1 %, respectively), while EAod9T had less than 97.0 % similarity to any other species of the genus Vibrio . Both strains share the basic characteristics of the genus Vibrio , as they are Gram-stain negative, motile, slightly halophilic, facultatively anaerobic bacteria. In addition, they are oxidase-negative and unable to grow on…

Analysis of bacterial communities of infected primary teeth in a Mexican population

2020

Background The objective of this study was to describe the bacterial communities associated with pediatric patients with endodontic infections of temporal teeth by targeting the 16S rRNA gene using pyrosequencing. Material and Methods Microbiological samples were obtained from the lower primary molars of thirteen 13 pediatric patients with dental infections. An aspiration method for microbiological sampling was used. The identification of microbiota employing the pyrosequencing method by targeting the 16S gene was performed. Results Ribosomal 16S RNA gene sequences were amplified, obtaining a total of 16,182 sequences from 13 primary infected molars (13 different individuals) by pyrosequenc…

Editorial Commentary on “The role of periodontal microorganisms in the pathogenesis of myocardial infarction. From PCR techniques to microbiome seque…

2021

Reduced Apo-Fumarate Nitrate Reductase Regulator (ApoFNR) as the Major Form of FNR in Aerobically Growing Escherichia coli▿

2008

ABSTRACT Under anoxic conditions, the Escherichia coli oxygen sensor FNR (fumarate nitrate reductase regulator) is in the active state and contains a [4Fe-4S] cluster. Oxygen converts [4Fe-4S]FNR to inactive [2Fe-2S]FNR. After prolonged exposure to air in vitro, apoFNR lacking a Fe-S cluster is formed. ApoFNR can be differentiated from Fe-S-containing forms by the accessibility of the five Cys thiol residues, four of which serve as ligands for the Fe-S cluster. The presence of apoFNR in aerobically and anaerobically grown E. coli was analyzed in situ using thiol reagents. In anaerobically and aerobically grown cells, the membrane-permeable monobromobimane labeled one to two and four Cys res…

O2-sensing and O2-dependent gene regulation in facultatively anaerobic bacteria.

1995

Availability of O2 is one of the most important regulatory signals in facultatively anaerobic bacteria. Various two- or one-component sensor/regulator systems control the expression of aerobic and anaerobic metabolism in response to O2. Most of the sensor proteins contain heme or Fe as cofactors that interact with O2 either by binding or by a redox reaction. The ArcA/ArcB regulator of aerobic metabolism in Escherichia coli may use a different sensory mechanism. In two-component regulators, the sensor is located in the cytoplasmic membrane, whereas one-component regulators are located in the cytoplasm. Under most conditions, O2 can readily reach the cytoplasm and could provide the signal in …

Response of the oxygen sensor NreB to air in vivo: Fe-S-containing NreB and apo-NreB in aerobically and anaerobically growing Staphylococcus carnosus.

2009

ABSTRACT The sensor kinase NreB from Staphylococcus carnosus contains an O 2 -sensitive [4Fe-4S] 2+ cluster which is converted by O 2 to a [2Fe-2S] 2+ cluster, followed by complete degradation and formation of Fe-S-less apo-NreB. NreB·[2Fe-2S] 2+ and apoNreB are devoid of kinase activity. NreB contains four Cys residues which ligate the Fe-S clusters. The accessibility of the Cys residues to alkylating agents was tested and used to differentiate Fe-S-containing and Fe-S-less NreB. In a two-step labeling procedure, accessible Cys residues in the native protein were first labeled by iodoacetate. In the second step, Cys residues not labeled in the first step were alkylated with the fluorescent…