The Determination of Concentrations in the Ultracentrifugation of Two‐Component Systems

1954 ◽  
Vol 22 (3) ◽  
pp. 555-559 ◽  
Author(s):  
R. Trautman ◽  
V. N. Schumaker ◽  
W. F. Harrington ◽  
H. K. Schachman
Keyword(s):  
Component Systems ◽  
Two Component ◽  
Two Component Systems

THE CRITICAL TEMPERATURES AND PRESSURES OF THE THREE TWO-COMPONENT SYSTEMS COMPRISED OF CARBON DIOXIDE, METHYL ETHER AND PROPYLENE

1932 ◽  
Vol 6 (5) ◽  
pp. 458-470 ◽  
Author(s):  
C. A. Winkler ◽  
O. Maass
Keyword(s):  
Carbon Dioxide ◽  
Methyl Ether ◽  
Critical Temperatures ◽  
Compound Formation ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
First Time ◽  
Three Components

The so-called critical temperatures and critical pressures for two-component systems are defined. For the first time three two-component systems have been investigated, involving three components taken two at a time. The three components were propylene, methyl ether and carbon dioxide. An experimental technique involving several new features is described. Accuracy in the determination of both critical temperatures and pressures is claimed. The system sulphur dioxide-methyl ether was also examined and the conclusions of previous investigators regarding compound formation confirmed. The results of the other three systems are analyzed and a theoretical discussion of these results reserved for a later publication.

Diffusive layering during film growth in two-component systems with limited mutual solubility

2000 ◽  
Author(s):  
Grigory V. Merkulov ◽  
Valentin M. Ievlev ◽  
Evgeny V. Shvedov ◽  
Vadim P. Ampilogov
Keyword(s):  
Film Growth ◽  
Mutual Solubility ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

scholarly journals Regulation of virulence and β-lactamase gene expression in Staphylococcus aureus isolates: cooperation of two-component systems in bloodstream superbugs

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sanaz Dehbashi ◽  
Hamed Tahmasebi ◽  
Behrouz Zeyni ◽  
Mohammad Reza Arabestani
Keyword(s):  
Staphylococcus Aureus ◽  
Real Time ◽  
Real Time Pcr ◽  
Quantitative Real Time Pcr ◽  
Gene Expressions ◽  
Resistance Development ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
Lactamase Gene

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA)-bloodstream infections (BSI) are predominantly seen in the hospital or healthcare-associated host. Nevertheless, the interactions of virulence factor (VFs) regulators and β-lactam resistance in MRSA-BSI are unclear. This study aims to characterize the molecular relationship of two-component systems of VFs and the expression of the β-lactamase gene in MRSA-BSI isolates. In this study, 639 samples were collected from BSI and identified by phenotypic methods. We performed extensive molecular characterization, including SCCmec type, agr type, VFs gene profiles determinations, and MLST on isolates. Also, a quantitative real-time PCR (q-RT PCR) assay was developed for identifying the gene expressions. Results Ninety-one (91) S. aureus and 61 MRSA (67.0%) strains were detected in BSI samples. The presence of VFs and SCCmec genes in MRSA isolates were as follows: tst (31.4%), etA (18.0%), etB (8.19%), lukS-PVL (31.4%), lukF-PV (18.0%), lukE-lukD (16.3%), edin (3.2%), hla (16.3%), hlb (18.0%), hld (14.7%), hlg (22.9%), SCCmecI (16.3%), SCCmecII (22.9%), SCCmecIII (36.0%), SCCmecIV (21.3%), and SCCmecV (16.3%). Quantitative real-time PCR showed overexpression of mecRI and mecI in the toxigenic isolates. Moreover, RNAIII and sarA genes were the highest expressions of MRSA strains. The multi-locus sequence typing data confirmed a high prevalence of CC5, CC8, and CC30. However, ST30, ST22, and ST5 were the most prevalent in the resistant and toxigenic strains. Conclusion We demonstrated that although regulation of β-lactamase gene expressions is a significant contributor to resistance development, two-component systems also influence antibiotic resistance development in MRSA-BSI isolates. This indicates that resistant strains might have pathogenic potential. We also confirmed that some MLST types are more successful colonizers with a potential for MRSA-BSI.

Monte Carlo Simulation of Electronic Excitation Migrationand Trappingin Disordered Two-Component Systems. A Comparison with Analytical Theories

1989 ◽  
Vol 44 (4) ◽  
pp. 257-261 ◽  
Author(s):  
Sławomir Błonski ◽  
Czesław Bojarski
Keyword(s):  
Monte Carlo ◽  
Electronic Excitation ◽  
Two Component System ◽  
Component System ◽  
Steady State Fluorescence ◽  
Donor And Acceptor ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems ◽  
Viscous Solution

Abstract Monte Carlo simulations of quantum yield and anisotropy of fluorescence in two-component systems have been conducted with various donor and acceptor concentrations and Förster radii ratios RDAO/RDDO. The influence of excitation migration and trapping on the fluorescence of the viscous solution has been considered. The results of the simulations have shown that steady-state fluorescence of a two-component system depends on the RDAO/RDDO ratio as predicted in LAF theory.

Global chromosome topology and the two-component systems in concerted manner regulate transcription in Streptomyces

2021 ◽  
Author(s):  
Martyna Gongerowska-Jac ◽  
Marcin Jan Szafran ◽  
Jakub Mikołajczyk ◽  
Justyna Szymczak ◽  
Magdalena Bartyńska ◽  
...  
Keyword(s):  
Topoisomerase I ◽  
Dna Supercoiling ◽  
Complex Life Cycle ◽  
Two Component System ◽  
Bacterial Gene ◽  
Component System ◽  
Global Regulators ◽  
Component Systems ◽  
Two Component ◽  
Two Component Systems

Bacterial gene expression is controlled at multiple levels, with chromosome supercoiling being one of the most global regulators. Global DNA supercoiling is maintained by the orchestrated action of topoisomerases. In Streptomyces, mycelial soil bacteria with a complex life cycle, topoisomerase I depletion led to elevated chromosome supercoiling, changed expression of significant fraction of genes, delayed growth and blocked sporulation. To identify supercoiling-induced sporulation regulators, we searched for S. coelicolor transposon mutants that were able to restore sporulation despite high chromosome supercoiling. We established that transposon insertion in genes encoding a novel two-component system named SatKR reversed the sporulation blockage resulting from topoisomerase I depletion. Transposition in satKR abolished the transcriptional induction of the genes within the so-called supercoiling-hypersensitive cluster (SHC). Moreover, we found that activated SatR also induced the same set of SHC genes under normal supercoiling conditions. We determined that the expression of genes in this region impacted S. coelicolor growth and sporulation. Interestingly, among the associated products is another two-component system (SitKR), indicating the potential for cascading regulatory effects driven by the SatKR and SitKR two-component systems. Thus, we demonstrated the concerted activity of chromosome supercoiling and a hierarchical two-component signalling system that impacts gene activity governing Streptomyces growth and sporulation.

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