scholarly journals High Production of 2,3-butanediol by a Mutant Strain of the Newly Isolated Klebsiella pneumoniae SRP2 with Increased Tolerance Towards Glycerol

2017 ◽  
Vol 13 (3) ◽  
pp. 308-318 ◽  
Author(s):  
Md. Shafiqur Rahman ◽  
Chunbao (Charles) Xu ◽  
Kesen Ma ◽  
Malaya Nanda ◽  
Wensheng Qin
Keyword(s):  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
High Production

Purification and characterization of 4-hydroxybenzoate 3-hydroxylase from a Klebsiella pneumoniae mutant strain

1995 ◽  
Vol 164 (1) ◽  
pp. 70-77
Author(s):  
Mónica Suárez ◽  
M. Martín ◽  
Estrella Ferrer ◽  
Amando Garrido-Pertierra
Keyword(s):  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
Purification And Characterization

Enhancement of ethanol production from glycerol in a Klebsiella pneumoniae mutant strain by the inactivation of lactate dehydrogenase

2012 ◽  
Vol 47 (1) ◽  
pp. 156-159 ◽  
Author(s):  
Baek-Rock Oh ◽  
Jeong-Woo Seo ◽  
Sun-Yeon Heo ◽  
Won-Kyung Hong ◽  
Lian Hua Luo ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Klebsiella Pneumoniae ◽  
Ethanol Production ◽  
Mutant Strain

scholarly journals Isolation and characterization of nitrogenase MoFe protein from the mutant strain pHK17 of Klebsiella pneumoniae in which the two bridging cysteine residues of the P-clusters are replaced by the non-coordinating amino acid alanine

1996 ◽  
Vol 318 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Faridoon K YOUSAFZAI ◽  
Martin BUCK ◽  
Barry E. SMITH
Keyword(s):  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
Specific Activity ◽  
Relative Distribution ◽  
Wild Type ◽  
Surface Charges ◽  
Ph Profile ◽  
Mofe Protein ◽  
Isolation And Characterization ◽  
Specific Activities

Nitrogenase MoFe protein (Kp1) from the mutant strain pHK17 of Klebsiella pneumoniae has been purified to give three catalytically active fractions. In this mutant, each of the two bridging cysteine ligands to the P-clusters, α-Cys-89 and β-Cys-94, has been replaced by a non-coordinating residue, alanine. SDS/PAGE and earlier native gels showed that the three fractions retained the normal α2β2 tetrameric form of wild-type Kp1; therefore we conclude that in each of the fractions the subunits are folded differently, thus resulting in different surface charges and allowing separation of the fractions on ion-exchange chromatography. Earlier EPR and magnetic CD data had shown that the mutant fractions contain P-clusters, and thus the mutated residues are not as essential for maintaining the integrity of the P-clusters as they appear from the X-ray structure. The specific activity of each of the three fractions was less than that of wild-type Kp1, the most active fraction having only 50% of wild-type activity. No change in substrate specificity or in the relative distribution of electrons to various substrates was found. The relationship between ATP hydrolysis and substrate-reducing activity, the EPR spectra of the S = 3/2 spin state of the iron–molybdenum cofactor (FeMoco) and the pH profile of acetylene-reduction activities of the three fractions did not differ significantly from those exhibited by wild-type Kp1. The specific activities of the three mutant fractions and of wild-type Kp1 were linearly proportional to the intensity of the S = 3/2 EPR signal from the FeMoco centres. This implies that those molecules of the three mutant fractions and the wild-type protein that contain EPR-active FeMoco are fully active, i.e. that the Cys to Ala substitution of the P-cluster ligands does not affect the specific activity of the protein. This in turn implies that the P-clusters are not directly associated with the rate-limiting step in enzyme turnover. We conclude that the lower specific activities of the mutant fractions are observed because the fractions are mixtures of species containing a full complement of FeMoco and P-clusters and species lacking some or all of these clusters. On the basis of the Mo contents and EPR spectroscopy of the mutant fractions, we propose that the loss of the P-clusters causes (i) the physical loss or inhibition of binding of some FeMoco; (ii) the EPR and catalytic inactivation of some FeMoco; and/or (iii) the incorporation of a FeMoco-like species into the FeMoco site of the mutant molecules.

scholarly journals SdiA, a Quorum-Sensing Regulator, Suppresses Fimbriae Expression, Biofilm Formation, and Quorum-Sensing Signaling Molecules Production in Klebsiella pneumoniae

2021 ◽  
Vol 12 ◽  
Author(s):  
Thaisy Pacheco ◽  
Ana Érika Inácio Gomes ◽  
Nathália Maria Gonçalves Siqueira ◽  
Lucas Assoni ◽  
Michelle Darrieux ◽  
...  
Keyword(s):  
Cell Division ◽  
Quorum Sensing ◽  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bacterial Cells ◽  
Gram Negative

Klebsiella pneumoniae is a Gram-negative pathogen that has become a worldwide concern due to the emergence of multidrug-resistant isolates responsible for various invasive infectious diseases. Biofilm formation constitutes a major virulence factor for K. pneumoniae and relies on the expression of fimbrial adhesins and aggregation of bacterial cells on biotic or abiotic surfaces in a coordinated manner. During biofilm aggregation, bacterial cells communicate with each other through inter- or intra-species interactions mediated by signallng molecules, called autoinducers, in a mechanism known as quorum sensing (QS). In most Gram-negative bacteria, intra-species communication typically involves the LuxI/LuxR system: LuxI synthase produces N-acyl homoserine lactones (AHLs) as autoinducers and the LuxR transcription factor is their cognate receptor. However, K. pneumoniae does not produce AHL but encodes SdiA, an orphan LuxR-type receptor that responds to exogenous AHL molecules produced by other bacterial species. While SdiA regulates several cellular processes and the expression of virulence factors in many pathogens, the role of this regulator in K. pneumoniae remains unknown. In this study, we describe the characterization of sdiA mutant strain of K. pneumoniae. The sdiA mutant strain has increased biofilm formation, which correlates with the increased expression of type 1 fimbriae, thus revealing a repressive role of SdiA in fimbriae expression and bacterial cell adherence and aggregation. On the other hand, SdiA acts as a transcriptional activator of cell division machinery assembly in the septum, since cells lacking SdiA regulator exhibited a filamentary shape rather than the typical rod shape. We also show that K. pneumoniae cells lacking SdiA regulator present constant production of QS autoinducers at maximum levels, suggesting a putative role for SdiA in the regulation of AI-2 production. Taken together, our results demonstrate that SdiA regulates cell division and the expression of virulence factors such as fimbriae expression, biofilm formation, and production of QS autoinducers in K. pneumoniae.

Efficient production of ethanol from crude glycerol by a Klebsiella pneumoniae mutant strain

2011 ◽  
Vol 102 (4) ◽  
pp. 3918-3922 ◽  
Author(s):  
Baek-Rock Oh ◽  
Jeong-Woo Seo ◽  
Sun-Yeon Heo ◽  
Won-Kyung Hong ◽  
Lian Hua Luo ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
Crude Glycerol ◽  
Efficient Production

Optimization of Culture Conditions for 1,3-Propanediol Production from Glycerol Using a Mutant Strain of Klebsiella pneumoniae

2011 ◽  
Vol 166 (1) ◽  
pp. 127-137 ◽  
Author(s):  
Baek-Rock Oh ◽  
Jeong-Woo Seo ◽  
Sun-Yeon Heo ◽  
Won-Kyung Hong ◽  
Lian Hua Luo ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Mutant Strain ◽  
Culture Conditions ◽  
Optimization Of Culture Conditions
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