scholarly journals THE RATE OF BACTERIOPHAGE INACTIVATION BY FILTRATES OF ESCHERICHIA COLI CULTURES

1941 ◽  
Vol 24 (4) ◽  
pp. 437-445 ◽  
Author(s):  
Emory L. Ellis ◽  
John Spizizen
Keyword(s):  
Escherichia Coli ◽  
Salt Concentration ◽  
Gum Arabic ◽  
Soluble Starch ◽  
Reaction Scheme ◽  
High Salt ◽  
Inactivation Rate ◽  
Square Root ◽  
Low Salt ◽  
Phage Inactivation

1. The rate of inactivation of an anti-coli phage by filtrates of cultures of the homologous bacteria has been studied. 2. The inactivation rate at 37°C. is proportional to phage concentration and filtrate concentration. 3. At 0°C. the rate of phage inactivation becomes proportional to the square root of the filtrate concentration. 4. A reaction scheme to account for these observations is suggested and discussed. 5. This coli-phage is also inactivated by relatively large concentrations of soluble starch, inulin, gum arabic, and acetylated gum arabic. 6. The inactivation is markedly influenced by salt concentration, being rapid at moderate salt concentrations and slow at high or extremely low salt concentrations. 7. The inactivated phage cannot be regenerated by high salt concentrations, or by soaps.

Effect of Salt Concentration and Incubation Temperature on Formation of Histamine, Phenethylamine, Tryptamine and Tyramine During Miso Fermentation

1986 ◽  
Vol 49 (6) ◽  
pp. 423-427 ◽  
Author(s):  
K.-D. HENRY CHIN ◽  
P. E. KOEHLER
Keyword(s):  
Salt Concentration ◽  
Incubation Temperature ◽  
High Salt ◽  
Soybean Paste ◽  
Salt Level ◽  
Low Salt ◽  
Two Factors

Two factors, salt concentration and incubation temperature, were examined for their effect on the formation of histamine, phenethylamine, tryptamine and tyramine during miso (soybean paste) fermentation. Misos containing 5 and 10% NaCl were prepared and incubated at 25 and 35°C. The effect of each factor was determined from the chemical and microbiological changes in the misos during fermentation. Salt level was a significant factor in the formation of amines. Higher amine levels were found in low-salt (5% NaCl) formulations than in high-salt (10% NaCl) misos. Incubation temperature within the range of 25 to 35°C during fermentation had little effect on amine formation in misos.

scholarly journals Osmoregulation of Dimer Resolution at the Plasmid pJHCMW1 mwr Locus by Escherichia coli XerCD Recombination

2002 ◽  
Vol 184 (6) ◽  
pp. 1607-1616 ◽  
Author(s):  
Huong Pham ◽  
Ken J. Dery ◽  
David J. Sherratt ◽  
Marcelo E. Tolmasky
Keyword(s):  
Escherichia Coli ◽  
Central Region ◽  
High Salt ◽  
Recombination Reaction ◽  
Recombination Site ◽  
Site Specific ◽  
Site Specific Recombination ◽  
E Coli ◽  
Low Salt ◽  
Ionic Effects

ABSTRACT Xer-mediated dimer resolution at the mwr site of plasmid pJHCMW1 is osmoregulated in Escherichia coli. Whereas under low-salt conditions, the site-specific recombination reaction is efficient, under high-salt conditions, it proceeds inefficiently. Regulation of dimer resolution is independent of H-NS and is mediated by changes in osmolarity rather than ionic effects. The low level of recombination at high salt concentrations can be overcome by high levels of PepA or by mutating the ARG box to a sequence closer to the E. coli ARG box consensus. The central region of the mwr core recombination site plays a role in regulation of site-specific recombination by the osmotic pressure of the medium.

scholarly journals Characterization of the RNA Synthesizing Activity of Isolated Kidney Nuclei

1975 ◽  
Vol 28 (6) ◽  
pp. 465
Author(s):  
CJ Story ◽  
J FW heldrake
Keyword(s):  
Activation Energy ◽  
Salt Concentration ◽  
Rna Synthesis ◽  
High Salt ◽  
High Salt Concentration ◽  
Limiting Factor ◽  
Isolated Kidney ◽  
Exogenous Dna ◽  
Low Salt

The limiting factor in RNA synthesis by isolated kidney nuclei is RNA nucleotidyltransferase at high salt concentrations but at low salt concentrations template availability becomes limiting. oc-Amanitin inhibits 85 % of the activity at high salt concentrations but only 20-50 % of the activity at low salt concentrations. Exogenous DNA is utilized at low salt concentrations [up to O�lM (NH4hS041 but not at high salt concentrations. The effect of increasing salt concentration is mainly to cause an increase in the length of chains synthesized. Initiation rates are not increased by high salt concentrations. The apparent Km for UTP is 8-10 11M at high salt concentrations, indicating that assays performed at low UTP concentrations are likely to give inaccurate results. The activation energy for the reaction at low salt concentration is less than that for the reaction at high salt concentration. The RNA synthesizing capacity of kidney nuclei is dependent on the method of isolation, and preparation by a modification of the Chauveau method (Chauveau et al. 1956) yields the most active nuclei.

Synthesis and conformation of sequential basic polypeptides with branched and linear side chains

1985 ◽  
Vol 50 (12) ◽  
pp. 2925-2936 ◽  
Author(s):  
Štěpánka Štokrová ◽  
Jan Pospíšek ◽  
Jaroslav Šponar ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Salt Concentration ◽  
Salt Solution ◽  
Theoretical Work ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cd Spectra ◽  
Low Salt ◽  
Conformational Freedom ◽  
Basic Polypeptides

Polypeptides (Lys-X-Ala)n and (Lys-X-Gly)n in which X represents residues of isoleucine and norleucine, respectively, and polypeptide (Tle-Lys-Ala)n, were synthesized via polymerization of 1-hydroxysuccinimidyl esters of the appropriate tripeptides to complete previously studied series. Circular dichroism (CD) spectra of the respective polymers were measured as a function of pH and salt concentration of the medium. The results were correlated with those obtained previously with the same series containing different amino acid residues at the X-position. The helix forming ability of the polypeptides (Lys-X-Ala)n with linear X side chain was found to be independent of the length. In the series (Lys-X-Gly)n the unordered conformation was the most probable one except (Lys-Ile-Gly)n. This polymer assumed the β conformation even in low salt solution at neutral pH. An agreement with some theoretical work concerned with the restriction of conformational freedom of amino acid residue branching at Cβ atom with our experimental results is evident.

How Optimized Is the Translational Machinery in Escherichia coli, Salmonella typhimurium and Saccharomyces cerevisiae?

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Xuhua Xia
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Salmonella Typhimurium ◽  
Codon Usage ◽  
Translational Efficiency ◽  
Square Root ◽  
Translational Machinery ◽  
Mutual Adaptation ◽  
Trna Species

Abstract The optimization of the translational machinery in cells requires the mutual adaptation of codon usage and tRNA concentration, and the adaptation of tRNA concentration to amino acid usage. Two predictions were derived based on a simple deterministic model of translation which assumes that elongation of the peptide chain is rate-limiting. The highest translational efficiency is achieved when the codon recognized by the most abundant tRNA reaches the maximum frequency. For each codon family, the tRNA concentration is optimally adapted to codon usage when the concentration of different tRNA species matches the square-root of the frequency of their corresponding synonymous codons. When tRNA concentration and codon usage are well adapted to each other, the optimal content of all tRNA species carrying the same amino acid should match the square-root of the frequency of the amino acid. These predictions are examined against empirical data from Escherichia coli, Salmonella typhimurium, and Saccharomyces cerevisiae.

Sand priming improves alfalfa germination under high-salt concentration stress

2006 ◽  
Vol 34 (1) ◽  
pp. 199-204 ◽  
Author(s):  
J. Hu ◽  
X.J. Xie ◽  
Z.F. Wang ◽  
W.J. Song
Keyword(s):  
Salt Concentration ◽  
High Salt ◽  
High Salt Concentration

scholarly journals A procedure for the rapid purification of Escherichia coli deoxyribonucleic acid-dependent ribonucleic acid polymerase (Short Communication)

1973 ◽  
Vol 133 (1) ◽  
pp. 201-203 ◽  
Author(s):  
Peter Humphries ◽  
David J. McConnell ◽  
Robert L. Gordon
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Short Communication ◽  
Gel Filtration ◽  
High Salt ◽  
Rapid Procedure ◽  
Complete Purification ◽  
Rapid Purification

A rapid procedure involving DNA–cellulose chromatography followed either by sedimentation in a high-salt glycerol gradient or by gel filtration is described for the complete purification of Escherichia coli DNA-dependent RNA polymerase.

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