Electron Transport through Early Exponential-Phase Anode-GrownGeobacter sulfurreducensBiofilms

2014 ◽  
Vol 1 (11) ◽  
pp. 1957-1965 ◽  
Author(s):  
Sarah M. Strycharz-Glaven ◽  
Jared Roy ◽  
Darryl Boyd ◽  
Rachel Snider ◽  
Jeffrey S. Erickson ◽  
...  
Keyword(s):  
Electron Transport ◽  
Exponential Phase ◽  
Early Exponential Phase

scholarly journals Analysis of Dibenzothiophene Desulfurization in a Recombinant Pseudomonas putida Strain

2008 ◽  
Vol 75 (3) ◽  
pp. 875-877 ◽  
Author(s):  
Javier Calzada ◽  
Mar�a T. Zamarro ◽  
Almudena Alc�n ◽  
Victoria E. Santos ◽  
Eduardo D�az ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Exponential Growth ◽  
Exponential Phase ◽  
Cell Process ◽  
Growth Phases ◽  
Early Exponential Phase ◽  
Sharp Maximum ◽  
Resting Cell

ABSTRACT Biodesulfurization was monitored in a recombinant Pseudomonas putida CECT5279 strain. DszB desulfinase activity reached a sharp maximum at the early exponential phase, but it rapidly decreased at later growth phases. A model two-step resting-cell process combining sequentially P. putida cells from the late and early exponential growth phases was designed to significantly increase biodesulfurization.

scholarly journals Pyruvate metabolism by aminopterin-inhibited Aerobacter aerogenes

1968 ◽  
Vol 106 (2) ◽  
pp. 367-373 ◽  
Author(s):  
M. Webb
Keyword(s):  
Reductive Amination ◽  
Exponential Phase ◽  
Carboxyl Group ◽  
Keto Acid ◽  
Secondary Products ◽  
Oxidative Deamination ◽  
Pyruvate Metabolism ◽  
Early Exponential Phase ◽  
Aerobacter Aerogenes ◽  
Acid Precursor

1. The synthesis and utilization of both alanine (by reductive amination, oxidative deamination and transamination) and valine (by transamination only) in Aerobacter aerogenes are unaffected by aminopterin. These amino acids, which accumulate in aminopterin-treated cultures of this organism, are therefore considered to be formed as secondary products from the excess of pyruvate that also accumulates. 2. Oxidative metabolism of pyruvate and the synthesis of acetylmethylcarbinol by A. aerogenes cells are unaltered by growth in the presence of aminopterin. 3. Cells from static and anaerobic cultures that have been treated with the folic acid antagonist in the early exponential phase have a decreased ability to cleave pyruvate to acetate and formate, and to effect the exchange of formate with the carboxyl group of pyruvate. 4. 3-Methyl-2-oxobutanoate, the keto acid precursor of valine, cannot replace pyruvate as substrate in either the phosphoroclastic or the exchange reaction.

scholarly journals Dynamics of COVID-19 pandemic at constant and time-dependent contact rates

2020 ◽  
Vol 15 ◽  
pp. 28 ◽  
Author(s):  
Marek Kochańczyk ◽  
Frederic Grabowski ◽  
Tomasz Lipniacki
Keyword(s):  
Incubation Period ◽  
Reproduction Number ◽  
Exponential Phase ◽  
Contact Rate ◽  
Epidemic Spread ◽  
Early Exponential Phase ◽  
Contact Rates ◽  
Serial Interval ◽  
Hypothetical Scenario ◽  
Multiplication Coefficient

We constructed a simple Susceptible−Exposed–Infectious–Removed model of the spread of COVID-19. The model is parametrised only by the average incubation period, τ, and two rate parameters: contact rate, β, and exclusion rate, γ. The rates depend on nontherapeutic interventions and determine the basic reproduction number, R0 = β/γ, and, together with τ, the daily multiplication coefficient in the early exponential phase, θ. Initial R0 determines the reduction of β required to contain the spread of the epidemic. We demonstrate that introduction of a cascade of multiple exposed states enables the model to reproduce the distributions of the incubation period and the serial interval reported by epidemiologists. Using the model, we consider a hypothetical scenario in which β is modulated solely by anticipated changes of social behaviours: first, β decreases in response to a surge of daily new cases, pressuring people to self-isolate, and then, over longer time scale, β increases as people gradually accept the risk. In this scenario, initial abrupt epidemic spread is followed by a plateau and slow regression, which, although economically and socially devastating, grants time to develop and deploy vaccine or at least limit daily cases to a manageable number.

scholarly journals Comparative studies on Salmonella typhi grown in vivo and in vitro II. The effect of extracts from normal and infected organs on the bactericidal serum action on strains grown in vivo and in vitro

1963 ◽  
Vol 61 (1) ◽  
pp. 21-30 ◽  
Author(s):  
A. L. Olitzki ◽  
Ophira Kaplan
Keyword(s):  
Growth Phase ◽  
Complement System ◽  
Salmonella Typhi ◽  
Exponential Phase ◽  
Antigenic Structure ◽  
Bactericidal Action ◽  
Early Exponential Phase ◽  
Lower Extent

The sensitivity of in vitro- and in vivo-grown strains of S. typhi was determined not only by their antigenic structure, but also by their growth phase. An increased vulnerability to the antibody-complement system has been found in cells during the lag and the early exponential phase, while non-multiplying cells devoid of any nutrient were almost invulnerable to the antibody-complement system. Extracts of organs from normal and infected animals may promote the growth of S. typhi, and, therefore, increase its vulnerability to the antibody-complement system. The majority of extracts from organs of mice infected with strain Ty 2 inhibited markedly the bactericidal action of serum on this strain and, to a lower extent, on strain O 901.

The bifunctional peptidoglycan lysin of Streptococcus agalactiae bacteriophage B30

Microbiology ◽  
2004 ◽  
Vol 150 (7) ◽  
pp. 2079-2087 ◽  
Author(s):  
David G. Pritchard ◽  
Shengli Dong ◽  
John R. Baker ◽  
Jeffrey A. Engler
Keyword(s):  
Calcium Ions ◽  
Lysozyme Activity ◽  
Exponential Phase ◽  
Site Directed Mutagenesis ◽  
Oral Streptococci ◽  
Early Exponential Phase ◽  
Conserved Sequence ◽  
Endopeptidase Activity ◽  
Reducing Activity ◽  
Group B

A group B streptococcal (GBS) bacteriophage lysin gene was cloned and expressed in Escherichia coli. The purified recombinant enzyme, calculated to have a molecular mass of 49 677 Da, lysed GBS cells. The susceptibility of GBS cells to lysis by the enzyme depended upon the growth stage at which they were harvested, with early exponential phase cells most sensitive. Calcium ions enhanced the activity of the enzyme. The enzyme also lysed other β-haemolytic streptococci, including groups A, C, E and G streptococci, but not common oral streptococci, including Streptococcus mutans. The generation of both reducing activity and N-terminal alanine residues during lysis indicated that the lysin is a bifunctional enzyme, possessing both glycosidase and endopeptidase activities. This is consistent with the presence of two conserved sequence domains, an Acm (acetylmuramidase) domain associated with lysozyme activity, and a CHAP (cysteine, histidine-dependent amidohydrolases/peptidases) domain associated with endopeptidase activity. Site-directed mutagenesis of conserved cysteine and histidine residues in the CHAP domain and conserved aspartate and glutamate residues in the Acm domain confirmed their importance for lysozyme and endopeptidase activity respectively.

scholarly journals Post-translational regulation of the RpoS and PsrA genes in pseudomonas putida WCS358: The role of ClpXP protease

2008 ◽  
Vol 60 (1) ◽  
pp. 1-4
Author(s):  
B. Jovcic ◽  
Jelena Begovic ◽  
Jelena Lozo ◽  
Lj. Topisirovic ◽  
M. Kojic
Keyword(s):  
Western Blot ◽  
Pseudomonas Putida ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Translational Regulation ◽  
Stationary Phases ◽  
Transcriptional Regulators ◽  
Exponential Phase ◽  
Early Exponential Phase

The RpoS and PsrA proteins are key transcriptional regulators that are activated in response to the stationary phase of growth in pseudomonads. This study was designed to establish whether ClpXP (ATP-dependent serine protease) regulates levels of RpoS and PsrA in Pseudomonas putida WCS358. Western blot analysis of P. putida WCS358 protein extracts from the early exponentianl, late exponential, and stationary phases of growth with antibodies against RpoS and PsrA revealed that these proteins are degraded by ClpXP in the early exponential phase of growth. The obtained results demonstrate a role for ClpXP protease in post-translational regulation of proteins encoded by the rpoS and psrA genes in Pseudomonas spp.

scholarly journals Gene expression of Pseudomonas aeruginosa in a mucin-containing synthetic growth medium mimicking cystic fibrosis lung sputum

2010 ◽  
Vol 59 (9) ◽  
pp. 1089-1100 ◽  
Author(s):  
Carina Fung ◽  
Sharna Naughton ◽  
Lynne Turnbull ◽  
Pholawat Tingpej ◽  
Barbara Rose ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Stationary Phase ◽  
Luria Broth ◽  
Exponential Phase ◽  
Anaerobic Growth ◽  
Phase Growth ◽  
Early Exponential Phase

Pseudomonas aeruginosa airway infection is the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. Various in vitro models have been developed to study P. aeruginosa pathobiology in the CF lung. In this study we produced a modified artificial-sputum medium (ASMDM) more closely resembling CF sputum than previous models, and extended previous work by using strain PAO1 arrays to examine the global transcription profiles of P. aeruginosa strain UCBPP-PA14 under early exponential-phase and stationary-phase growth. In early exponential phase, 38/39 nutrition-related genes were upregulated in line with data from previous in vitro models using UCBPP-PA14. Additionally, 23 type III secretion system (T3SS) genes, several anaerobic respiration genes and 24 quorum-sensing (QS)-related genes were upregulated in ASMDM, suggesting enhanced virulence factor expression and priming for anaerobic growth and biofilm formation. Under stationary phase growth in ASMDM, macroscopic clumps resembling microcolonies were evident in UCBPP-PA14 and CF strains, and over 40 potentially important genes were differentially expressed relative to stationary-phase growth in Luria broth. Most notably, QS-related and T3SS genes were downregulated in ASMDM, and iron-acquisition and assimilatory nitrate reductase genes were upregulated, simulating the iron-depleted, microaerophilic/anaerobic environment of CF sputum. ASMDM thus appears to be highly suitable for gene expression studies of P. aeruginosa in CF.

Sign in / Sign up

Export Citation Format

Share Document